This snow managed to insinuate itself everywhere. The pickup was parked outside, and this is what we saw when we opened the hood.

This is the drift created by the Forsythia bush south of the house. This picture hardly does it justice.




I suspect that the rock you're looking at is some variety of limestone or dolostone. Without being able to do some basic field tests I can't be more certain. Limestone would react vigorously in weak acid, whereas dolostone would visibly react with acid only if powdered. Both would be scratched by steel or glass....and the second from the Kansas Geological Survey:
The Kansas Geologic Survey geological map for Brown County indicates the nearest bedrock is Pennsylvanian-aged rocks of the Wabaunsee Group. It's impossible for me to say from here exactly where you fall in the overall stratigraphy of that group but it's constituted dominantly of shale with a number of limestone formations interspersed.
[...] I hesitate to go much beyond that without seeing the rocks firsthand. I do suspect that some of those rocks on your blog post (the ones that show concentric zonations, particularly) are showing post-depositional effects of interaction with groundwater, either during the process of diagenesis (original solidifaction of the sediments) or during subsequent hydrothermal events or weathering. [...]
Sincerely,
Ron Schott
Department of Geology
Fort Hays State University
According to Bob Sawin, a geologist here who has studied this area, these are stromatolites, a kind of fossilized algae from the Pennsylvanian Period of geologic history, roughly 300 million years ago. You can learn more about them at http://en.wikipedia.org/wiki/Stromatolite.
These are actually fairly common in various Pennsylvanian and Permian rock units in eastern Kansas. Bob says these are from a rock layer called the Soldier Creek Shale, which is part of a formation called the Bern Shale. Here's a scientific reference about them (though this is a publication that would probably be pretty hard to find, and would undoutedly tell you more than you need to know).
Sawin, R.S., West, R.R., and Twiss, P.C., 1985, Stromatolite Biostrome in the Upper Carboniferous of Northeast Kansas, /in/, Dutro, J. T., Jr., and Pfefferkorn, H. W., (eds.), Compte Rendu IX International Congress of Carboniferous Stratigraphy and Geology, vol. 5, Paleontology, Paleoecology, and Paleogeography, Southern Illinois University Press, Carbondale and Edwardsville, Illinois, p. 361-372.
Rex Buchanan
Deputy Director, Outreach and Public Service
Kansas Geological Survey
Elizabeth Bennet in Pride and Prejudice by Jane Austen