54 The American Geologist. jan. isoo. 
"Buena Vista is in the great valley which extends from Canada to 
Alabama, and which is noted for its limestone lands, iron beds, clear 
streams, healthful climate, picturesque scenery, the number of its 
towns and its substantial population. The valley is known in Penn- 
sylvania as the Lehigh, Cumberland, etc., where it abounds in natural 
resources and acquired wealth. In northern Virginia it is the Shenan- 
doah valley. In the middle it originates the James and the Roanoke 
rivers. Southwardlit is known as southwest Virginia, where now is in 
progress a remarkable scene of industrial development." 
While this is essentially an economic report, its descriptions, based 
on a comprehensive knowledge of the geology of the region, give an 
accurate and valuable account of its iron ore beds, clays, ochres and 
sands, and of its limestones, cements, water power and general agri- 
cultural capabilities. For its scope it is a model popular geological 
report. 
Development of some Silurian Brachiopoda. Chas. E. Beecher and 
John M. Clark, Albany. 3fem. N. Y. State Museum, vol. i, No. 1, 4to, 
8 plates, pp. 95. 
This is a valuable addition to the science of the brachiopoda. It indi- 
cates the developmental changes in the life-histories of twenty-five 
species, some of them with great fulness, and makes known the 
dangers that surround the paleontologist who publishes new names for 
small variations in form. The plates are very instructive, and ought 
to be imitated in the treatment of other genera. 
The authors have made use of the very abundant material afforded 
by collections from Waldron, Indiana, to trace the individual develop- 
ment of all the species of brachiopods known from the Niagara shales 
in that interesting locality. 
To give some conception of the amount of material at their command 
it is stated that the collections when received weighed about seven 
tons. After specifically separating the mature specimens and all that 
were approximately mature, some fifty thousand immature individuals 
for the most part less than five millimeters in length, were gathered 
from the washings of the slabs. The result is that for a large propor- 
tion of the brachiopod species the authors are able to show a series of 
individuals beginning with forms in some instances less than a milli- 
meter in length and including every stage of growth up to the aged 
adult with its greatly thickened margin and crowded lines of growth. 
Some of the rarer species have afforded no young specimens, while 
among the really common forms, Rhynchonella stricklandia and Whitfieldia 
(Meristina) maria are particularly remarkable for the absence, or al- 
most entire absence, of immature individuals. 
"The method of illustration which has been adopted is one which 
seems most readily to furnish a means for comparison of characters. 
The embryonic shells are represented as enlarged, usually to the size 
of an adult, and accompanying the enlargement are natural size pre- 
resentations of the final result of normal growth. Where the mature 
