adam , Sabre52 , Mark K , NRG , vegasjames
I have no doubt that Adam found that shell out there, and that it was there naturally, not dropped off by a hippy, lol. I have a friend that lived in Seeley twenty or so years ago. Although I never saw it, she described a snail (gastropod) shell she found somewhere out there. From her description, it was most likely about the same size, and it also had a bright pink interior. Sadly, as soon as it was exposed to sunlight, the pink coloring started to fade. After a time (not sure how long, maybe a few years?), there was no color left at all. She had taken it to a museum, and was told what it was. The museum personnel were not so impressed, said it was "only" x-number (10,000?) years old. Long time ago, don't remember the details.
In Ocotillo Wells, mrrockpicker found a small cylindrical piece of possibly coral, that when found, was a brilliant hot pink on one end, turning to purple on the other. It must have been recently unearthed and exposed to the sun jus before it was found. It has since faded considerably, despite being indoors out of bright sunlight. I can imagine it would be totally bleached out if left in the intense desert sun!
I have also found many types of gastropod shells, both semi fossilized, with some intact shell, and others that are only inside casts (steinkerns), some filled with calcite. These were found from Painted Gorge area (north of I-8, east of Coyote Mountains) in the south, north to Ocotillo Wells area. They also exist in the Anza Borrego Desert State Park, but I have not done any exploring or collecting there (it is forbidden!). Not all shells become total fossilized, or turned into hard stone.
I am not so familiar with shell ID, so don't know if it is a conch or not. But, after some online searching, I found a "Systematic List of Fossil Invertebrates from the Anza-Borrego Desert State Park Region." www.borregospringschamber.com/abdsp/documents/jefferson.htm Among many other things, it listed four species of conchs (on Table 3) found in the park!
Family Strombidae (conchs)
Strombus galeatus
S. gracilior
S. granulatus
S. obliterates
I looked up photos of each of these, but can't say for certain if Adam's find is one of them. It seems conchs have a more pointier spiral. But how interesting that conchs have even been found there!
Another possibility is
Family Cassidae (helmet snails)
Cassis subtuberosus
This desert area in my backyard has had an interesting geologic history. 10 million to 15 million years ago, the Baja peninsula began to tear away from mainland Mexico, opening up the space now filled by the Gulf of California. The waters of this ancient gulf, often called the Imperial Sea, inundated the land as far north as present-day Palm Springs area in Riverside County.
Many of the marine fossils are closely related to forms from the Caribbean Sea. They document a time before the Isthmus of Panama formed, when the warm Gulf Stream of the western Atlantic Ocean invaded eastern Pacific Ocean waters.
Around 5 million years ago, the Colorado River began slicing through Arizona to form the Grand Canyon. The rock it carved away was carried downstream and deposited in a wide delta at the head of the gulf. The turbid, silty waters buried corals but formed a shallow muddy bottom so suitable for oysters that they formed thick reefs. Corals require clear water in order to photosynthesize. Other life forms that could handle the silty, more brackish water became more prevalent.
New fossils are continually exposed in the Vallecito badlands and other areas of the park. And paleontologists continue to find marine fossil remains of corals and spiral casts of the inside of shells that filled with cemented sand then leached away.
The shapes help them identify the animals that formed these structures. In some cases, they are clearly recognizable – nearly identical to sea biscuits and conchs you might find today, if you were diving in the Caribbean.
The similarity between the fossils and modern oceanic creatures suggests the waters of this ancient sea must have been like those in the modern Caribbean – warm and clear – in order for these tropical species to have thrived.
Back then, ocean waters flowed freely between the Caribbean and the Imperial Sea because the Isthmus of Panama didn't exist. Between 3 million and 2.5 million years ago, Panama rose up from the seafloor and halted the flow between the tropical Atlantic and Pacific oceans. That shut down a tropical current, and changed ocean circulation patterns – and climates – throughout the world.
Rather suddenly, the tropical fossils disappear from the rock layers, and oysters and clams, things found in brackish, muddy waters, emerge. These more recent fossils are encased within fine, silty stone that formed of mud – evidence of an entirely different sort of environment.
The ancient Colorado continued to bring sediment down river, building up the river delta at the northern end of the Sea of Cortez (Gulf of California), and eventually blocking it off. I'm sure there were other forces at work, such as techtonics, but over the years, the area went from an inland salt water sea, to a shallow, brackish sea, to a river (estuarine) environment, than lake (lacustrine). Fossils from all these periods exist here. I have even found fossils of animals that did not live here, but were brought into the area from points north, by the ancestral Colorado River. How do I know? I found a fossilized rugose coral that went extinct before the sediments were laid down out there. The time horizon did not match, had to have come from elsewhere.
I have a few gastropod shells I'll take photos of and post later today. Nothing like what Adam found, however!
Hope you didn't find this too boring.
Jean