58 
IOWA ACADEMY OP SCIENCES. 
fauna, and its record of anomalous conditions of deposition. 
In the field the distinction between the Le Claire and the Ana- 
mosa stages are even more easily recognized, though faunally 
the two stages are intimately related. In the Anamosa stage 
oblique bedding is unknown; lithologically the rock is an 
earthy, finely and perfectly laminated dolomite, not highly 
crystalline in its typical aspect, and too impure for the manu- 
facture of lime. It may be quarried in symmetrical blocks of 
any desired dimensions, while the Le Claire limestone breaks 
into shapeless masses wholly unfit for building purposes. The 
quarry beds of the Anamosa stage are quite free from fossils, 
but along the Cedar river in Cedar county the brachiopod fauna 
of the upper part of the Le Claire reappears in great force in a 
stratum four feet in thickness, up near the top of the forma- 
tion. The beds of the Anamosa stage are very undulating, and 
dip in long, graceful, sweeping curves in everj^ possible direc- 
tion. The knobs and bosses and irregular undulation devel- 
oped on the sea bottom as a result of the peculiar condition 
prevailing during the Le Claire age, persisted to a greater or 
less extent after the age came to an end, and it was upon this 
uneven fioor that the Anamosa limestone was laid down. The 
puzzling fiexures of the Anamosa limestone, and the puzzling 
variations in altitude at which it occurs, were largely deter- 
mined by irregularities in the upper surface of the Le Claire 
formation. 
THE BUCHANAN GRAVELS: AN INTERGLACIAL 
DEPOSIT IN BUCHANAN COUNTY, IOWA. 
BY SAMUEL CALVIN. 
About three miles east of Independence, Iowa, there are 
cross-bedded, water-laid deposits of sand and gravel of more 
than usual interest. The beds in question occur near the line 
of the Illinois Central railway. The railway company indeed 
has opened up the beds and developed a great gravel pit from 
which many thousands of carloads have been taken and used as 
ballast along the line. 
Overlying the gravel is a thin layer of Iowan drift, not more 
than two or three feet in thickness, but charged with gray 
