UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 5, No. 13, pp. 217-223, Pis. 17-18 ANDREW C. LAWSON, Editor 



NOTES ON THE OSTEOLOGY OE THE 

 THALATTOSAURIAN GENUS 

 NECTOSAURUS. 



BY 



John C. Merriam. 



Contents. 



PAGE 



Introduction 217 



Skull and dentition 218 



Arches and limbs 219 



Vertebrae and ribs 220 



Conclusions 222 



Introduction. 



During the summer of 1906 an expedition from the University 

 of California visited the exposures of the Hosselkus Limestone in 

 the Upper Triassicof Shasta County, California, with the purpose 

 of making a special search for material representing the recently 

 described thalattosaurian reptiles. 1 A few scattered bones of 

 Nectosaurus were found in the basal layer of the upper or mas- 

 sive, grey horizon of the limestone near Brushy Slope camp on 

 the western side of Brock Mountain, but the greater part of the 

 material representing this genus was obtained in a narrow belt 

 of limestone near the North Fork of Squaw Creek. In the North 

 Fork exposures numerous scattered bones including Neciosaurus, 

 Shastasaurus, and Thalattosaurus were obtained in a stratum 

 evidently representing the top of the blue, shaly lower division 

 of the Hosselkus Limestone, or the base of the massive, grey 



tThe Thalattosauria. Merriam, J. C, Mem. Calif. Acad., Vol. 5, No. 1. 



