siltstone - teaching student specimens of a gray Miocene siltstone from the Ridge Basin, California UNIT OF 5 SPECIMENS
This siltstone is Miocene in age, is moderately lithified, and was deposited in a closed basin in a non-marine or brackish marine depositional environment. It is mapped as a unit the Ridge Route Formation, part of the Ridge Basin Group. The cement is calcium carbonate which will effervesce with a drop of dilute hydrochloric acid. These are well-enough cemented that they will withstand student examination.
The silt grains in these specimens are smaller than those of a sandstone and and feel gritty when rubbed. It would be instructive to compare this siltstone with one that is cemented with silica, and with a sandstone.
Shipping: Priority Mail small flat rate box unless combined with other purchases.
Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. A link in that invoice will bring you back to checkout, no hassle.