Review of Recent Geological Literature. 39] 
Paleozoic types of that genus and family. Had he called it a Modio 
lopsia and placed it near M. pholadiformis Hall, all must have been 
satisfied until the discovery of its internal parts shall have given us 
more reliable evidence of its true position in nature. Again we do not 
see why his species fucoida should be referred, even doubtfully, 1" 
Rauffella, nor where he gets his information that R. fllosa Ulrich, is. 
like his species, " branched at regular intervals." The writer has seen 
over a hundred specimens of R.filosa and not one showing any evidence 
of branching-. Finally, it is to be observed, that the illustrations are of 
an inferior order, while the paper contains more typographical errors 
than are usually found in scientific publications although perhaps the 
author is not responsible for these defects. e. o. u. 
Missouri Geological Survey, Sheel Report No. i. Report on Mine in 
Motte sheet. By l'n vkles Rolltn Keyes. (132 pp., 14 pis., map, Jef 
ferson City, 1895.) In this report Dr. Keyes deals with an area of ex- 
ceptional interest in that it includes at once many of the more impor- 
tant localities for the study of the Ozark uplift, and one of the oldest 
and best known mining regions of North America. • It was at the Mine 
la Motte that the early French explorers in 1720 found the lead depos- 
its said to have been even previously known to the Chickasaw Indians. 
Since that date mining has been continuously carried on. and among 
the ores taken out may be mentioned lead, iron, copper, manganese, 
nickel, cobalt and silver. More recently a large quarry industry has 
grown up, and granite, porphyry, limestone, marble and sandstone are 
all quarried. The rocks exposed within the area covered by the sheet 
include (1) the Knob Lick granite, (2) Iron Mountain porphyry. (3) La 
Motte sandstone, (4) Fredericktown limestone, (5) Le Sueur limestone. 
The granite and the porphyry are referred to the pre-Cambrian and are 
quite fully described by Keyes and Haworth jointly. The sedimentary 
beds are separated from the crystallines by a marked unconformity and 
are considered to belong to the Cambrian. The areas covered by the 
different formations are shown upon one of the excellent maps being is- 
sued by the Missouri survey, the geology being by Keyes and Haworth 
and the topography by Lonsdale and Theilman. 
The crystallines occupy the central and southwestern portion of the 
area, the elastics being laid down againsl them. The sedimentary beds 
have an important dip away from the crystallines along the contact, bul 
become horizontal within a limited distance to the northeast. Folds are 
.unimportant and faults, with the exception of that at Mine la Motte. 
are of small throw. Fumarole action is shown only at the silver mines 
where quartz veins are also found. Dykes of basic material fill in joint 
crevices in the crystallines, but are earlier than the elastics. The granite 
and porphyry are eruptive and belong to a single magma. The area is 
a region of super-imposed streamways. The crystalline hills of the 
southwest are semi-alpine in character and rise to a dissected peneplain 
referred to the Tertiary. The chert hills of the northeast rise to the 
same plain. Between these two lies the broad Farmington lowland. 
