CARBONIFEROUS AGE. 169 



animal, already referred to, and which is frequently called fossil 

 wheat or rice. It is, however, a lowly animal, classed with the 

 protozoans, and known as Fusilina cylindrica. The shell is small, 

 half cylindrical and bluntly pointed at the end, and a\eraging about 

 the size of a grain of rice. Its shell is composed of seyen or eight 

 closely coiled whorls. Unlike its condition in Europe, it here 

 ranges all through the coal measures. It is questionable whether 

 it is anywhere in America as abundant as it is here in Nebraska. 

 In Johnson County in many places around Tecumseh, it constitutes 

 almost the entire fabric of many rocks, often from four to ten feet 

 in thickness. It is often present in enormous numbers in shale, 

 and where it is decomposed, hundreds can be picked up, already by 

 the decomposition of the matrix lying loose and cleansed ready to 

 be placed in a cabinet. All along the carboniferous exposures in 

 Nebraska, it is abundant, in limestone, sand stone and shale. The 

 massiye compact limestone from Stout's quarry, on the north side 

 of the Platte, at South Bend, contains immense numbers of these 

 Fusilina, which giyes the rock great beauty when polished. 



Corals, which are now confined to low latitudes, were abundant 

 in Nebraska during Carboniferous times. Fiye species have thus 

 far been identified here. The most characteristic grew into a 

 curious form remotely resembling a short ram's horn. It is known 

 by the name of Campophylluni torquium. A loose bed of shale in 

 the bluffs at Rock Bluffs contains an immense number of them. 



The Crinoids were represented by seven species at least, and 

 some of them existed in great numbers. While the heads of these 

 sea lilies, as they are sometimes called, are only occasionally found, 

 owing no doubt to their original fragile character, their screw-like 

 stems are abundant in all the rocks. 



As elsewhere during Carboniferous times molluscan life flourished 

 here. The Polyzoa were represented by eight, and the Branchi- 

 opods by twenty six species, of which eight were Producti.* 

 Among these one known as Productus Semireliculatus is quite large 

 and was one of the most abundant animals in these old Carbon- 

 iferous seas. Those known as P. lotixispinus, P. praltenianus, and 

 P. Nebraskensis are also abundant. Two species of thin flat shells 

 called chonetes gramclifera and C. glabra, make up the almost entire 

 mass of some limestone rock at Plattsmouth and other places along 

 the Missouri. No shell is perhaps so widely dispersed as the one 



♦The Producti are now mostly classed with the Articulata. 



