SearchResearch Challenge (8/28/24): How can you find search phrases beyond your own brain's power to imagine?

 A real challenge... 

The "Walkie Talkie" building in central London has a giant unanticipated consequence. At certain times of day, the windows reflect the sun's rays to a point creating a hot spot that can damage cars unlucky enough to be parked at the focus.

  ... for doing online research (what we call SRS) is figuring out what to use for the search terms and phrases.

For most people and for most research questions, figuring out what search terms to use is not a huge problem--in truth, people mostly look up fairly simple things.  (What's the phone number of my local pharmacy?  When is the swimming pool open?  Is there a grocery store near me?)  The vast majority of online searches are like that--straightforward requests for information.  

But then every so often you land in a really difficult research swamp, and it's tough to figure out how other people would write about the very concepts you're interested in learning about. 

As you no doubt know by now, I'm working on a new book about Unanticipated Consequences (see my earlier post about this).  And even though I'm a full couple of years into the project, I find myself STILL trying to figure out how to find books, articles, web pages, podcasts, news stories (etc.) on the topic. 

That's why today's SRS Challenge is all about how to deal with this kind of problem.  

Suppose you're doing research on a topic that's big, complicated, and difficult to render in just a few words.  How do you start to search for such a beast? More particularly: 

1. What can a researcher do to find other words and phrases that would help in doing online searching for such a topic?  Let's consider my topic--unanticipated consequences--how can we find other helpful search terms and phrases to seek out and understand this topic?  Ideas?  

2. Same question, except this time I want to search for books on the topic of unanticipated consequences.  (Yes, I know I can go to Amazon, Barnes and Noble, AbeBooks, Google Books, or the Internet Archive.)  What's the best way to find the top 10 books on the topic? 

Note that we want to learn HOW you'd find such search terms or books.  What process did you follow to come up with search terms that work for your last big, complex, and tricky search?  

Tell us in the comments! 

Keep searching. 

Answer: Finding the earliest aerial photo in your area?

 Photos from the heavens... 

Early aerial photo by Gaspard-Félix Tournachon, aka Nadar, from a hot air balloon.
Near Montmartre, Paris, 1866. P/C Wikimedia.

 In my searches this week I found, as Howard Carter said when peering into Tut's tomb for the first time, "... I see marvelous things," including this shot of the pyramids at Giza, photographed from Eduard Spelterini's balloon on November 21, 1904.  

Giza Pyramid complex. Eduard Spelterini, 1904.  Wikimedia.  

This is a great example of kinds of EARLY pix were were seeking.  Recall that your Challenge this week was to... 

1. What's the best way to find the earliest possible aerial photos taken of some area?  As we work on this, tell us how you found the earliest aerial images of the place where you live (Vancouver Island, Mexico City, Portugal, Rio de Janeiro, etc.)  

It's one thing to find an image... but more importantly: What lessons should we learn about finding aerial photos?  IS there a general method for finding historic aerial imagery?  Or does every place have it's own special and particular story?  

Once again, I spent way too much time on this.  (There's something about archival imagery that just grabs my imagination and doesn't let go.)  

A little background: The first aerial photograph is widely considered to be one taken in 1858 by French photographer and balloonist Gaspard-Félix Tournachon, also known as "Nadar". Nadar took the photo from a tethered hot-air balloon 80 meters above the French village of Petit-Becetre, took eight separate images on a glass plate negative. Unfortunately, his original photographs are long gone, so the earliest surviving aerial photograph was taken by James Wallace Black in Boston, 1860. He caught a ride in Samuel Archer King's hot-air balloon, the "Queen of the Air" while it was tethered at Boston Common. 

 

I bring this up because it was really hard to get decent aerial photos before 1900.  There were some photos taken from kites, blimps, and even pigeons, but not many, and mostly made for specific purposes. 

 Julius Neubronner, Die Brieftaube als Photograph, in: Die Umschau, JG 12, Nr 41, 1920.  Link.

For even more fun background information, see the Wikipedia article on Aerial Photography.  Aerial images made in these very early days are widely available and often spectacular, but they're not collected anywhere in particular--it's just sort of hodge-podge. Search for your location / subject + aerial photography (maybe add in "kite" or "pigeon" or "balloon" into the search). But don't spend a lot of time on this--the number of images is small.

 

It wasn’t until the First World War that aerial photography took off (so to speak), with commercial photography services springing up.  The best known in the US was Fairchild Aerial Surveys. 

 

Meanwhile in the UK the big post-war aerial photo service was Aerofilms.  (It’s changed hands a few times—the images are available at National Collection of Aerial Photography).   

You can sometimes find the earliest images of a location by searching for a location + kite. When you do this for San Francisco, you'll end up finding the images immediately after the 1906 earthquake as seen from a kite flying over the east side of San Francisco. It's worth clicking on this image as it's pretty high res. (As a local, I can recognize many of the streets even now, 118 years later.)

Kite photo by George Lawrence of San Francisco after the earthquake of 1906. P/C Wikimedia

 

I bring this all up because... knowing the history of aerial photography is important in finding the images.  Most aerial images I’ve been able to find are in collections at libraries, archives, and museum.  And most often, they’re organized by location AND by the company or organization that collected the image. 

 

As my Maps Librarian friend Zoe wrote: “Aerial photography is sometimes publicly available, sometimes privately held or in copyright restriction. It can be indexed or preserved at the municipal, county, state level as well as other jurisdictions, as well as by land management agency in the case of state, federal, and tribal lands.” 

That caution of "sometimes" available is really true. Many collections require money, sometimes a LOT of money to access their pics.

With all that as warning, what CAN you do to find older aerial images?

To do a good search for OLDER aerial imagery, you’ll have to figure out WHERE you’ll want to look, WHEN you want to look, what ORGANIZATION holds the images, and the NAME of the outfit that created (or collected) the images. 

 

For instance, at Airphotos you’ll find the Benjamin and Gladys Thomas Air Photo Archives at the UCLA Department of Geography.  This includes images from the Spence Collection and the Fairchild Collections.  The Spence Collection is from Spence Air Photos, Inc. – All oblique low altitude black and white aerial photographs taken between the years 1918-1971.  The Fairchild photos are all from Southern California taken between 1927 and 1964.  The collection is huge, but most of it requires that you pay $80/hour if you ask them to do the research, or $40/hour if you visit in person. The biggest problem is that they don't really have overview images, so you can't really see what you're going to get. Great collection, but not exactly handy.

 

There’s also the Hatfield Aerial Surveys, available through the Online Archive of California (and the Stanford Archives - and a guide to searching the Stanford Archives). They're mostly aerial photographs of the Stanford University campus and Palo Alto. They're useful to me, but probably not to anyone outside of the 94304 Zip Code.

The point here is that you should try to search in an area, discover what collections exist AND who made them, then search for that collection by name.

For example, to find archival aerial photos of Rochester, NY (where I went to graduate school), I searched for:

[ Rochester NY aerial photograph ]

which led me to learn about the USA School of Aerial Photography, now collected at the Museum of Flight Digital Collections. Once there, I could use the search tool on their website [Rochester aerial photograph] and find a nice set of images. The same trick will probably work for your location.

Sample of the Museum of Flight Digital Collections

Point is, every place has their own set of collections.  You have to find the collection first, then dig in through their interfaces to find what you seek. 

In addition....  places that have some archival aerial images probably have some that are NOT part of their collection, but which are just scattered around and used kind of randomly.  

For instance, at Stanford, you can search on the Stanford.edu site for "aerial photographs" and discover the Stanford Atlas, which just happens to have a set of aerial images, many of which are not part of the Hatfield Survey. 

The deeper lesson here is that you need to find a plausible place that might collection archival photos (e.g., a local history museum, a university, a city library, a local archive) and then spend some time searching through their resources.  

Curious about the history of San Antonio, TX, I looked for their city website (santanio.gov), then did a site: search on Images.Google.com... and then filtered by color to black-and-white.  (I don't bother with filtering by dates because many photo dates are the date-of-scanning or date-of-upload.  Dang it.)  

Here's what that looks like-- [ site:sanantonio.gov aerial ]

Of course, if you search for a library, museum, or archive in San Antonio, you can quickly find UTSA Libraries Special Collections, which has a number of lovely archival aerial images that you can filter by date.  (In this collection, the date is actually the date the image was created.  Very nice.)    Note that I've done a search for all "aerial" images, and then time restricted the images.  

Aerial View of Alamo Plaza San Antonio, General Photograph Collection, 083-1019,
UTSA Special Collections

 

Most places seem to have some kind of aerial collection--the challenge is to find it (and then the next challenge is to figure out how to use each collection's sometimes wonky interface).  

A nice listing of Texas photograph collection can be found here Texas Historical Imagery Archive.  

 * 

What about the more general case?  Here's a listing of some of the US nation-wide collections you might consider:  

USGS Earth Explorer: The U.S. Geological Survey (USGS) provides access to satellite and aerial images of various areas. It's especially useful for historical aerial photography.  (However... Difficult to use.  Often you can find the image metadata, but then you have to go elsewhere to actually download or purchase the images.)  

OpenAerialMap: A platform that offers free and open access to a variety of aerial imagery collected from different sources.  (But really spotty coverage. Very little in my area.) 

Historic Aerials: Good collection, but very similar to Google Earth's archive image function.  Costs money (and has annoying ads).    

Google Earth: There is a web version of Earth, but the application is MUCH better.  It's very easy to look back in time.  Here are the Google Earth images of Montmartre from 1949 and 2023. Contrast these with the photo at the top of the post taken by balloon in 1866. 

SearchResearch Lessons 

When you're searching for archival aerial images, there are a few things to keep in mind... 

1. Not everything is online--Trust me on this. A LOT of archival images are still stashed away in archive and library collections.  You might have to physically visit the collection in order to find what you really need.  Don't pass up the chance to visit the archive in person.  (You cannot believe the things I've found just because I was there.  The number of times an archivist has said to me "this isn't cataloged yet, but I think you'll find it interesting" is amazing.  Don't miss the chance to visit! 

2. Images are often in collections, but often NOT in the collection you might expect.  I managed to find a bunch of great aerials of San Francisco from the 1920s... in the collection of the University of Nebraska.  Keep your search broad and run down all of those leads.  You never know when you'll find the aerial image you want. 

3. When doing image searches, switch to black-and-white mode when you can.  That often helps limit your searches to early images. 

4. Call the librarian or archivist!  Really!  I made about a dozen calls when researching this post, and uniformly, they answered the phone (or actually called back).  Real humans are a great resource, especially as they can translate what you really meant to say into a working search.  

5. Realize and accept that searching for images is about the trickiest thing you can do.  The language and technology is complicated, but that's why you're a SearchResearcher!  You can learn words like orthoquad and understand why they're useful.  Spend the time to learn about the field--it will pay off. 

Keep searching! 

SearchResearch Challenge (8/14/24): Finding the earliest aerial photos from your area?

 Photos from the heavens... 

Early aerial photo by Gaspard-Félix Tournachon, aka Nadar, from a hot air balloon.
Near Montmartre, Paris, 1866. P/C Wikimedia.

... can reveal marvelous things.  Here's a 19th century white horse depicting King George carved into the hillside in southeast England. 

Osmington White Horse from 1808.  P/C/ Google Earth (2024)

As we saw last week, it's possible to find aerial photos of a particular region, but often tricky to find ones that are exactly of the place you want, and taken at the time you want.  

The Uffington White Horse was created some time between 1380 and 550 BC,
during the late Bronze Age or early Iron Age. P/C Wikimedia A recent photo
of an ancient image. 

In searching for the shellmounds of the San Francisco Bay Area, I was constantly looking at images that were close... but not quite on target.  Or I was looking at images that were a decade too late for the traces I was seeking.  

I bet I'm not the only person with this issue.  So let's do some collective problem-solving on this and figure out... 

1. What's the best way to find the earliest possible aerial photos taken of some area?  As we work on this, tell us how you found the earliest aerial images of the place where you live (Vancouver Island, Mexico City, Portugal, Rio de Janeiro, etc.)  

I wanted early aerial images of the area close to Stanford, Palo Alto, and Mountain View.  I found some.  More importantly: What lessons should we learn about finding aerial photos?  IS there a general method for finding historic aerial imagery?  Or does every place have it's own special and particular story?  

Let us know in the comment thread below.  

Keep searching! 

Even more: Can you find the shellmounds?

 Fascinating... 

Shellmound in Emeryville, CA, party torn apart. From Publications in American Archaeology and
Ethnography Journal, V 23 (1926)

Last week's Challenge was great fun, and as I mentioned, I spent a lot of time on this.  The Challenge definitely captured my Joy of Search!    

The original motivation for the Challenge came from walking past this bronze plaque that's in my neighborhood.  

But I have to take a this week off from SRS as I'm spending the next few days in Atlanta doing a annual site review for an NSF AI and healthcare project (AI-CARING).  Each year, NSF invites a small panel of folks in the field to review the work done over the past year and suggest, if needed, any changes to the plan.  So I'm kinda busy this week. 

However... as I mentioned, I found a LOT of material that I couldn't quite compress into last week's post.  If you looked through the comments, you'll see that lots of Regular Readers also found fascinating materials as well.  

One of the motivations for the Challenge was walking past this plaque at the corner of Middlefield Road and Webster Street, very near Marion Avenue in Palo Alto. 

 I looked high and low for an aerial photo of this area (or of the Castro and/or Ponce Shellmounds) taken before 1948.  I know that in 1948 the Castro shellmound was in the process of being deconstructed and sold as fertilizer.  You saw the best pix I could find in last week's story.  I just was not able to find great aerial photos from the before times.  Unfortunately.  

Interestingly, if you look up this plaque, you'll quickly find an essay by Benjamin Wright about this location, its geology, and the mounds that were here and how they were made.   

As he wrote: 

"The Muwekma/Ohlone would collect shellfish on a daily basis during the winter months, as it was their main staple at that time of the year. According to [Margolin], they typically returned to their villages with a day’s catch that was usually abundant. By the year’s end “they had collected literally tons of mussels, clams, oysters, olivellas, crabs, gooseneck barnacles, abalones, and other shellfish. As centuries passed the discarded shells piled up at village sites to form mounds. Some of these mounds were as much as thirty feet deep, some a quarter of a mile across . . . ”  These shellmound sites, also referred to as middens, or shell middens, by archaeologists, were reinforced with a mixture of soil and refuse [Chartkoff and Chartkoff]. 

Searching in Newspapers.com with location set to Palo Alto and searching before 1960, you can find articles that discuss the mounds, their locations, and what happened to them.  Here are a couple of samples:  

The Peninsula Times Tribune, Nov. 27, 1906.— The interest of scientists has been aroused by the discoveries made at an old Indian mound at Castro station, three miles south of here. The mound is owned by J. P. Ponce of Mayfield, who has been using its soil for fertilizer. Many skeletons of wild animals and human beings were unearthed in addition to various Indian ornaments and a vast quantity of sea shells. Prof. Harold Heath and Prof. J. O. Snyder of Stanford have investigated the mound and propose to make further excavations and send a collection of the relics unearthed to the National museum at Washington. The mound is the largest, yet found in this valley, being two acres in extent.

Another news article describes it as 

"300 feet (100 meters) in diameter and 10 feet high...even at that time (1893) ..they were the sites of villages... and the mounds contained the discarded shells as well as the bodies of the departed...during the early days of Stanford, you really hadn't lived until you had gone down to Castro and dug yourself up a skeleton or two."  

The mound also contained... 

"...whistles made of birds' bones, flint arrow-heads, beads of abalone shells, and mortars and pestles are among the booty now resting in museums or in private homes."  (PTT, Nov 19, 1946) 

Of course, since the Native American made mounds near streams, and streams are just about everywhere in the Bay Area, it's no surprise that there were many mounds.  The Nelson map included some 425 sites, but the full Nelson report comments that "it is not to be supposed that 425 exhausts the evidences of aboriginal occupation..."  

In my searches I found yet another map of shellmounds made by local historian and part-time surveyor Jerome Hamilton in 1937.  This shows the shellmounds around the city of San Mateo, along San Mateo and Blackhawk creeks.  

P/C San Mateo Historical Association

This map is in the San Mateo County Historical Association archives.  I found a reference to it in my Google search for shellmound maps, and was amazed to learn that it wasn't online, but if you just could stop by and visit the archive, you could see the map in person.

I spent a while with the map.  If you measure the distance between the railroad and El Camino Real (the major street in the area--neither the street nor the railroad have probably moved much in the past 67 years), we find it's nearly 500 meters.  

If the shellmound shown in the map (number 12) is depicted accurately, it's roughly 166 meters wide, much larger than the Castro mound.  

It's not a huge surprise that there are so many shellmounds in the SF Bay Area--they seem to have be made where there were people and streams.  If there was a stream that flowed into the Bay, you could pretty much reliably find a mound next to it.  In the following map you can see another dozen or so sites that we not included in the Nelson 1909 map.  Here's just what I located by map-diving... note that there was a stream every mile or two.  

As a consequence, there are MANY mounds... including some that are still being discovered today as people dig up the soil to do new construction.  Example: The new construction at "Elco Yards" in Redwood City, 37.4800228683888, -122.22562046367638 , just north of Palo Alto by a few miles. In an article from 2013, artifacts and bones were discovered while digging causing a long pause while the site was excavated and the remains repatriated.  

After the Guide to Bay Area Creeks. Each red dot is a shellmound that I found via online research as described.  Original base map based on work Guide to San Francisco Bay Area Creeks

As several authors have noted, Native American groups pretty much made mounds everywhere they went.  In my immediate neighborhood between Adobe and Matadero Creeks, I found reports of 5 or 6 mounds.  All of them long gone--carted away for fertilizer or buried under omnipresent construction. Stanford University, just 15 minutes away by bicycle has at least 60 sites on campus.  Just to the left of the ninth tee on the campus course, on a rise overlooking the nearby road, is a curiously shaped rock with a circular depression on top. A plaque informs golfers that the outcropping is an Indian grinding stone, once used by the Muwekma-Ohlone people to crush acorns into flour.  It's a huge rock that was on a great site--near a stream and thousands of oak trees.  A great place to live and create a mound or two.  

Bottom line: This is all pretty much Native land everywhere, with home places, village, and mounds everywhere throughout the Bay Area.  With a bit of online search, you can discover truly remarkable things--in this case, traces of people who lived here long ago, and stories that I never knew.  

As always, Keep Searching! 

==============

Chartkoff, Joseph L., Kerry Kona Chartkoff. The Archaeology of California. Stanford U P, 1984. 

Margolin, Malcolm. The Ohlone Way: Indian Life in the San Francisco-Monterey Bay Area. Heyday Books, 1978.

Answer: Can you find the shellmounds?

It can be just too much fun... 

Shellmound in Emeryville, CA, party torn apart. From Publications in American Archaeology and
Ethnography Journal, V 23 (1926)

... and that's been the case here. 

It's fairly easy to answer the Challenge overtly, but looking up one thing leads inevitably to another in a chain of curious questions.  It's not ratholing, exactly, but I have spent an awful lot of time looking into this question.  

Here's last week's Challenge: 

1. I want to know if I NOW live near any Native American shellmounds. (By "near," I mean within 5 miles / 8km.)  Can you find a map that shows an extensive set of shellmounds in the SF Bay Area?  Are any of those near Mountain View, CA?   (Extra credit: Can you find any images of the nearest shellmounds?)   

The fast answer to this is to do a search like: 

      [ map shellmound San Francisco California ] 

and you'll find the Shellmound.org website, which has a lovely series of maps documenting the changes to the West Berkeley shellmound over the years.  On that site we read:

 "The archaeological site is officially known by the number CA-ALA-307, because archaeologist Nels Nelson gave the West Berkeley Shellmound #307 when he mapped 425 shellmounds around San Francisco Bay in 1904."  

That sounds like a map we need to find.  

Luckily, the second hit is a link to a Wikimedia map, labeled "Map of San Francisco Bay Area Showing Distribution of Shell Heaps."  Shell heaps is a synonym for Shellmound.  Following the links back, you'll find this map is from Nelson, Nels Christian. Shellmounds of the San Francisco Bay Region, Vol. 7. No. 4. University Press, 1909.  

This is the lower right corner of the map on page 349 where you can see: 

Shell Heap map by Nelson, 1904 Wikimedia (Note that this is a large, high-res file.)

See that entry for Mountain View (bottom center), with the town of Palo Alto just above Mayfield?  Just above Mountain View is "CASTRO," next to the long line indicating a railroad.  Just above CASTRO is a dot labeled 356.  Following the convention in the Shellmound.org site for labeling archaeological sites, we might try a search for "CA-SCL-356" and see what happens.  

(Why SCL?  Because in the site code above,  the ALA refers to "Alameda" county.  Mountain View, Palo Alto, and CASTRO are all in Santa Clara county.  Hence the 3-letter acronym SCL. These codes are known as Smithsonian trinomials. Most historic sites in the US have a trinomial.)  

So, let's guess that this is the naming convention for archaeological sites in California and search for:  

     [ "CA-SCL-356" ] 

This leads us quickly to the Cooley Landing: Cultural Resource Inventory and Assessment with this map in it:

The southern part of San Francisco Bay, showing major shellmounds in the area. 
This is a modified version of the map in the Cooley Landing report SMA-77 is
fairly near the Cooley Landing site. (after Hylkema, 1991)

The "Cooley Landing" report is an cultural resource assessment and inventory that's done before any major construction project can take place.  Such reports have been required ever since the passage of the National Environmental Policy Act in 1969. Before tearing up the place, the project has to write a comprehensive "cultural assessment" covering Native American places and artifacts.  

Such reports often have an impressive amount of detail about things like village sites, archaeological resources, and things like shellmounds.  In the Cooley Landing report we read that:

"Between 1909 and 1912, Lewellyn Loud from the University of California at Berkeley surveyed the South Bay and plotted the locations of many mound sites including clusters of them within, and adjacent to the project area. In 1912, Loud tested one such mound, SCL-1 (also known as the Ponce and Castro Mound and formerly designated by Nelson as SCL-356 in the City of Mountain View). This site was located within three miles of the current project location... It was noted that the mound was 8 feet high and broader than a football field."  Cooley Landing report

So now we know about a shellmound also known as the Castro Mound and another mound known as the Ponce mound (SCL-1).  

A quick search for: 

     [ Castro shell mound ] 

takes us to the Wikipedia page for the Monta Loma neighborhood in Mountain View, which also tells us that the Castro shellmound was there, reportedly 400 feet long, by 300 feet wide, and 10 feet high.  (121 m long, by 100 m wide, by 3.3 m high) 

I thought it would be nice to find an image of the mounds. I searched a nice archive of Mountain View historic photos (hosted by library), but don't find anything.  The town to the north is Palo Alto, so I thought I should try that.  Sure enough, a search for 

     [ Palo Alto historic photos ] 

leads to the Palo Alto Historical Association digital photo collection.  In that interface I searched for [mound], [shellmound], and find that both of those searches fail. 

However, adding the term INDIAN to the search--[Indian mound]--leads to the "Aerial view of Indian Mound" Shown below: 

Castro Shellmound (CA-SCL-356) P/C Palo Alto Historical Association,
Guy Miller photo collection.  (Ca. 1941)

Footnote:  Yes, I know the term "Indian" isn't politically correct, but it IS the index term of art.  Perhaps eventually all of the indexes in the world will be updated, but if you want to find something, you have to adopt the terminology that's in use in the database. 

This was fairly successful, but I thought perhaps I could find an aerial photo of the area of SCL-1 and SCL-356 at the Stanford Earth Sciences library.  There, with the help of their incredibly energetic and wonderfully helpful Map Librarian Zoe Dilles I was able to locate a few hundred photos, both in hardcopy prints, and at the UC Santa Barbara Collection called FrameFinder.  With Zoe's help I was able to dig deep in to the aerial photo archive and find a few images that come close, but are not quite high enough resolution to definitively pin down the location.  

The Monta Loma neighborhood. April 1, 1948.  Flight CDF5, Frame 2-83

I spent several happy hours looking through the various "flights" of aerial imagery that was from the late 1940s, I wasn't able to find anything that was obviously correct.  The shellmounds are in the above image, but it's hard to find them just visually.  (I think I see them, but it's a tough one to validate.)  

So... the bottom line here is that YES, there are several shellmounds in the Mountain View / Palo Alto area.  In fact, within a 10km (6.2 mile) radius of my house, I was able to identify at least 7 different shellmounds, none of which have any above-ground presence.  

Another helpful article in this search was There were once more than 425 shellmounds in the Bay Area. Where did they all go?  The short answer is that they were mined for the quality of the soil and/or for the artifacts within them.  (Turns out that giant piles of shells turn into high quality fertilizer over the years.)  

2. A big part of my family hails from the area around Rice Lake, WI.  Are there any Native American mound structures there?  If so, where?  

This wasn't hard either:  

     [ Rice Lake Wisconsin mounds ] 

quickly leads you to the Wisconsin First Nation's Rice Lake Mound group.  As they say on their web page, 

"The group once consisted of fifty-one conical burial mounds, apparently built after about a.d. 500. Some mounds were excavated in the nineteenth century by the Smithsonian Institution during its search for the identity of the mound builders, while others were excavated in the 1950s. Many were obliterated by city expansion." 

This has been, unfortunately, the fate of many mounds over the years.  But it is a lovely park: 

I have to say that I spent probably 30 hours on this Challenge... it was just WAAY too interesting.  The more I searched, the more I found.  I went to a couple of different museums and archives in doing this research--maybe I'll get around to telling you those stories another day.  

The thing that impressed me the most is exactly how much material is still available online, if you search across different resources.  We've talked before about how using multiple sources is a way to both triangulate AND to inform mutual lines of research.  

I didn't mention it here, but I also found that looking through archives of old newspapers (primarily Newspapers.com) was incredibly valuable for getting the same information in slightly different ways.  It's also fascinating to see what the reporting was like back in the day.  An article from the March 31, 1909 Peninsula Times Tribune (page 6) reports that "..“the Ponce, Huff, Rengstorff, Abelee, Crittenden, Farell, Somers, and Ynigo ranches all contain mounds.... Sanborn ranch had artifacts.  Ynigo was granted Rancho Posolomi, aka Rancho Yñigo.  Posolmi village was the name of the village..."  that was there before the Europeans moved in.  

The Ynigo ranch folks found "... mortars, sorcery stones, bone combs, abalone money, skeletons, hatchets, mussel, oyster, clam and small birds..." And, of course, arrowheads. 

In another article I found that at the location of the current Google X building, when the area was still being worked for initial construction in the 1960s, local boys could collect arrowheads and bits of pottery--things that were mostly taken home for personal displays.  

That was then.  Today, these are mostly invisible.  Some have been returned to the local First Nation tribes, but many, many things have vanished into the mists of history.  

SearchResearch Lessons

1. When you see codes that are meaningful, figure out what they are so you can use them too.  In this case, the Smithsonian trinomials are incredibly useful for finding inventories and assessments of cultural artifacts.  Learn what those codes are and use them.  

2. Look for maps.  People LOVE to make maps.  By searching for maps of cultural sites (esp. shellmounds), I was able to find a lot of shellmound locations that I hadn't expected.  

3. Keep in mind that your search terms might not be their search terms.  I started with shellmounds, but learned later that people often index them until "shell mounds" or "middens" or "shell heaps"... etc.  Similarly, if they use a term like "Indian" (especially in historical contexts), you'll have to use the terminology that they used to use, even if it's not what we would say today.  Put your mind back into their time and use the words they'd use.  (Remember we've talked about this before!  Effective searching with old terms.)  

Keep Searching!