536 PROCEEDINGS OF THE WASHINGTON MEETING 



The third paper was 



PRIMITIVE CHARACTERS OF THE TRIASSIC ICHTHYOSAURS 

 BY JOHN C. MEKRIAM 



[AbsiracQ 



Extensive collections of icbthyosaurian material which have recently been made 

 in the Upper Triassic of California have brought to light a considerable number 

 of species and genera heretofore unknown. Some of these forms exhibit peculiar 

 specializations not found in other representatives of the order. There are, however, 

 a number of primitive characters which are quite strongly marked. These characters 

 are of considerable interest, as they assist somewhat in the attempt to determine 

 the character of the primitive icbthyosaurian. 



Leaving out of account such characters as are doubtfully primitive, the following 

 are some of the structures indicating a less marked degree of specialization than is 

 found in the purely aquatic, fish-like ichthyosaurs of the Jurassic: 



1. Vertebral center either perforated or deeply biconcave. 



2. Either a larger number of cervical intercentra than in the Jurassic forms or 

 the atlas and axis simpler. 



3. Zygapophysial facets of cervical and dorsal vertebrae large, separate, and not 

 usually in the same plane. 



4. Neural spines in cervical and dorsal regions, thick, sometimes circular in cross- 

 section. 



5. Scapula, pubis, and ischium expanded distally, elements of pelvic arch gener- 

 ally robust. 



6. Hind limbs sometimes as large or larger than the anterior. 



7. Epipodial and phalangeal elements of anterior and posterior limbs generally 

 elongated and showing a median constriction. 



The fourth paper v^^as received from the Section E list, entitled 



PALEONTOLOGICAL WORK IN NEW YORK 

 BY JOHN M. CLARKE 



[Abstracf] 



(a) The Guelph reefs and their faunas. Recent investigations have shown an 

 excellent development of the Guelph fauna at at least two stages in the upper 

 Siluric dolomites of New York, and an analysis of the character of the species and 

 the nature of the inclosing rock indicates that the fauna flourished on and about 

 coral reefs in a shrinking sea. 



(6) The faunistic provinces of Portage time. In addition to the provinces al- 

 ready established during this stage in New York, namely, the eastern or Oneonta, 

 the central or Ithaca, the third or Naples (= true Portage), the last proves divisible 

 into subprovinces, depending on the degree to which this fauna invading from the 

 west penetrated eastward. The migration path of the fauna is from the northwest. 

 The " Portage" and " Girard shales " of Erie county, Pennsylvania, are later than 

 Portage time. The " Portage " of Kettle point and adjoining localities — Ontario — 

 is the black shale facies onlv. 



