362 CARNEGIE INSTITUTION OF WASHINGTON. 



important collection was made a few years ago by Dr. W. K. Moore- 

 head, of Phillips Academy, from a fissure near Cavetown, Maryland; 

 still another was made for the writer about 3 years ago from a cave 

 near San Antonio, Texas. 



As a sort of by-product of his work on the Pleistocene, and compiled 

 mostly outside of office hours, the writer is preparing a continuation of 

 his Bibliography and Catalogue of Fossil Vertebrata of North America. 

 This is intended to bring the records up to date. 



Wieland, G. R., Yale University, New Haven, Connecticut. Associate in 

 Paleontology. (For previous reports see Year Books Nos. 2-4, 6-9, 

 11-17.) 



Cycadeoid and related studies earlier outhned have been continued, 

 except the investigation of Mesozoic gymnosperm stem structure. Here 

 material has still further increased and a broader field is outlined. 



In volume ii (Publication No. 34) on the petrified cycads, a sub- 

 sidiary attention was given to the cycadeous vegetation of the Jurassic 

 and later time. Following this same plan, in volume iii, in course of 

 preparation, a considerably more searching restudy of the Triassic 

 cycadophytes is being attempted. So far as the petrified series is con- 

 cerned, certain studies of finely conserved trunks, in interest recalling 

 the Cycadeoidea dartoni, are being added. In particular, through the 

 courtesy of the custodians of the State University of Iowa collection, 

 the remarkable original type of Macbride, Cycadeoidea dacotensis, is 

 now being sectioned at the U. S. National Museum. 



Some field work has also been done, and the Western localities have 

 been revisited for the purpose of locating the best point for quarrying 

 for petrified cycads. Two such quarries are now fairly located. Also, 

 in connection with the general subject of petrified forests, incidental 

 attention has been given to the remarkable Carboniferous forests of 

 this kind near Athens, Ohio, first reported by Lesquereux in 1859. 



The subject of the mode of dicotyl leaf modification from the more 

 gymnospermous and fern-like ancestral types of mid to lower 

 Mesozoic time was noted last year, and some headway has been made. 

 It is now clearer that there is an easy transition from the more primitive 

 blades (the Stangeria type) to bipinnate (specialized) types of cycad 

 fronds. Furthermore, that pinnate blades like those of the oleander 

 and magnolia find near antecedents in pinnate cycadeoid leaves has 

 been pointed out. This holds from both the morphologic and strati- 

 graphic viewpoint. But the general features of Lower Cretaceous 

 foliage show such a close transition from pinnate to palmate dicotyls 

 that both may be regarded as equally primitive, although the latter 

 appear the more abruptly. Hence the change from Jurassic to Creta- 

 ceous leaf-types could take place far more rapidly as a parallel move- 

 ment than as more local movements, or evolution of the kind hitherto 

 expressed by the so-called "paleontologic tree." 



