88 



University of California Publications in Geology [Vol. 12 



Geologic horizon. — Lower Etchegoin (Jaealitos) formation, Lower 

 Pliocene. Associated with Astrodapsis arnoldi arnoldi (Pack) and 

 Astrodapsis arnoldi var. depressus Kew. 



Localities. — Coalinga district, Fresno County, California, Univ. 

 Calif. Iocs. 2969 and 2973. 



ASTRODAPSIS AENOLDI, subsp. PELTOIDES (Anderson and Martin) 

 Plate 15, figures 2a, 2b, 3 



Astrodapsis peltoides F. M. Anderson and Bruce Martin. Proc. Calif. 



Acad. Sei., ser. 3, GeoL, vol. 4, 1914, pp. 52-53, pi. 2, fig. 2. 

 Astrodapsis peltoides Nomland. Univ. Calif. Publ. Bull. Dept. Geol., vol. 9, 



1916, p. 202 (listed). 



Holotype. — No. 102 Calif. Acad. Sci. Coll. Pal. ; topotype, speci- 

 men, no. 451 Calif. Acad. Sci. Coll. Pal. 



Size medium. Measurements of holotype : anteroposterior diameter 

 64.5 mm., transverse diameter 54 mm., greatest height 15.5 mm. Out- 

 line of test anteroposteriorly suboval to subcircular ; some specimens 

 notched in the ambulacral areas, the degree of notching being greater 

 in the two posterior ones ; margins thick, with the upper surface rising 

 immediately to a moderately elevated summit, which is anterior to the 

 center of the test and on the odd anterior ambulacral area. Apical 

 system central ; small and flush with the general surface of the test, 

 bi;t depressed below the highest points on the petals. Broad, deep 

 grooves are jiresent in the interambulacral areas, with smaller ones 

 in the ambulacral areas along the outer sides of the petals. Ambulacra 

 wide at the margin, the interambulcra being about one-third the width 

 of the ambulacra ; ambulacra petaloid. Petals usually narrow but some- 

 what variable in width ; inner rows of nearly rounded pores diverge 

 but little from the apical system, but on reaching their full extent 

 continue in approximately i3arallel lines until within about one-fourth 

 the distance from the margin, when they diverge slightly to the edge 

 of the test ; outer rows of pores diverge considerably at tirst and then 

 converge slightly and again diverge, the two rows of pores coming 

 close together when near the edge of the test. Each poriferous zone 

 equal to about one-third to one-half the width of the interporiferous 

 area. Petals more or less elevated, esi3ecially near the apical system ; 

 usually of the same width, though the odd anterior one may be slightly 

 narrower and the anterior pair somewhat wider than those of the 

 bivium. Inferior surface concave ; peristome small, sunken, and 



