258 The American Geologist. October, looi. 
supposed iliat ir. its early history the class had passed through a similar 
stage, which he called the Pentactaea and regarded as the ancestor of 
all echinoderms." 
The third theory seems to have broader foundations than either of 
the others. "Any theory of the origin and evolution of the echino- 
derms has to explain those features in the structure and life-history of 
living echinoderms to which attention has been called; it has to find 
pi a for the varied structures of extinct forms, more particularly the 
ancient crystids ; and it has to connect the echinoderms with some an- 
ecedent group, whose structure shall not be echinodermal, but compar- 
able with that of some more simple animals now known to us. * * * 
Opinion trends towards the belief that the most important of these 
steps was a fixed stage through which the group passed at an early 
period of its race-history, and the theory that this is the explanation 
of the peculiarities of echinoderm structure may be called the 'Pelma- 
tozoic theory.' " c. r. k. 
lozva Geological Survey, Volume XI. Administrative Reports. S.\M- 
UEL Calvjn, State Geologist; A. G. Leonard, Assistant State Geol- 
ogist. Des Moines, 1901 ; pp. 519, with 12 plates, 9 geological maps 
of counties, and .-13 figures in the text. 
This volume contains a statement of the progress of the survey 
during the year 1900, and of its chief directions of special investiga- 
tions, by Prof. Calvin ; a chapter on the mineral production of the state 
in that year, by Dr. S. W. Beyer; and detailed reports on the geology 
of I.ouisa and Pottawattamie counties, by Prof. J. A. Udden ; of Marion 
county, by B. L .Miller ; of Cedar county, by Prof. William H. Norton ; 
of Page county, bv Prof. Calvin : and of Clay and O'Brien counties, by 
Prof. Thomas II. MacBride. About half of the state has now been 
geologically mapped and described, including more than forty counties 
variously grouped throughout its whole area. 
It is announced that Dr. Beyer is preparing a monograph on the 
clays of Iowa ; that Prof. Norton is preparing a further report on ar- 
tesian wells, supplementing his previous work ; and that a monograph 
on the grasses of Iowa, by Prof. L. H. Pammel, is in press, to be is- 
sued as one of the publicatons of this survey. During the present year 
investigations of the present soils of the state were expected to be 
taken up by Mr. Milton Whitney, chief of the Soil Division of the 
United States Department of Agriculture. 
The production of coal in Iowa last year amounted to $6,977,466 ; of 
clay industries, $2,395,488; and of stone, gypsum, lead and zinc, and 
iron ore, together about $1,000,000. w. u. 
Structure and relations of Uintacrinus; by Frank Springer. (Mem. 
Mus. Comp. ZooL, Vol. XXV, pp. 1-90, 8 pis., Cambridge, 1901.) 
Ever since its discovery, the Cretaceous crinoid Uintacrinus has 
been of great interest to morphologists and paleontologists. So much 
has been written about this remarkable type of crinoid that it would 
seerh that nothing more worth recording remained to be told. Yet now 
