78 Scientific Intelligence. 



land Geological Survey. Baltimore, 1901. — The authors of the 

 first paper have drawn the distinction between stratigraphic and 

 paleontologic units ; but as they state, " the former are desig- 

 nated as formations and members, the latter as stages and sub- 

 stages. As their limits are the same the same name is employed 

 for each." Names are given in the following table: 



Group. Formations or stages. Members or substages. 



f -^ • j Woodstock 



Pamunkey. \ J J ) Potapaoo 



! Aquia. j Paspotansa 



I | Piscataway. 



The several members or substages are still further divided into 

 zones from which the faunules are obtained which are listed. 



The zones are apparently discriminated on a lithologic basis 

 and grouped together on a paleontologic basis into members. The 

 details are carefully worked out and the results are well arranged. 

 The only criticism the writer would suggest is that the discrimi- 

 nation between formation and fauna is not carried far enough to 

 exhibit the full value of the fossils in correlation. 



If the combination of species, called substages, is supposed to 

 be restricted to the formational divisions, called members, then 

 the paleontological statistics may serve to identify the members ; 

 but if the species instead of stopping their existence migrated 

 at the end of each member, the true value of the species in corre- 

 lation is not reached by applying the same name to the forma- 

 tional members and to the iaunal substages. 



The paleontological part has been (as it should be) assigned to 

 specialists. The whole fully keeps up the reputation these reports 

 have held from the beginning of the new administration. 



h. s. w. 



2. Annual Report of the Geological Survey of Arkansas for 

 1892. Vol. V., The Zinc and Lead Region of North Arkansas; 

 by John C. Brannee, State Geologist. Pp. 1-395, plates 1-38, 

 and figs. 1-92. Little Rock, 1901. — An appropriation made by 

 the Arkansas legislature in 1899 provided for the publication of 

 this volume, the investigation for which was completed before the 

 official termination of the Survey in 1893. 



The chief part hi the volume is concerning the zinc and lead 

 deposits of northern Arkansas. These ores were originally 

 deposited in sedimentary beds of the Ordovician age, and by 

 infiltrating waters were carried through fissures to form secondary 

 deposits in cavities in rocks of later age. 



The Paleozoic faunas of northern Arkansas, Chapter vii, pp. 

 268-362, by Henry S. Williams, is here published for the first 

 time. The report was prepared during the progress of the Sur- 

 vey, its detention having been caused by lack of appropriations 

 for its publication. The report contains a classification of the 

 Paleozoic formations of the northern part of the State, w T ith lists 

 of the contained faunas, and discussion of several complex strati- 



