IGNEOUS AND CRYSTALLINE ROCKS. 39 
S20 
EC 
The following analyses are of sedimentary rocks adjoining the dike: 
F. Calcareous sandstone. 
G. Fine-grained fissile sandstone. 
H. Indurated shale. 
I. Fragment of shale included in the peridotite. 
Il was dried five hours at 110° previous to analysis. 
2. CRITTENDEN COUNTY DIKE. 
A mica peridotite, described by Diller in Am. Jour. Sci., 3d ser., vol. 44, p. 286. 
Contains biotite, serpentine, and perofskite, with less apatite, muscovite, magnetite, 
salcite, chlorite, and some other secondary products. P. R. C. 800. 
A. The rock described by Diller. SR. 1 of casseliase. Analysis by W. F. Hille- 
brand, record No. 1241. 
B. An analysis of probably the same rock, from a shaft 40 feet deep at Marion. 
Collected by J. R. Procter, analyzed by L. G. Eakins, record No. 965. 
