Tlio faunii of Crawlisli (Joorjijo's consists of one luimlrotl ami rifty-tliroc 

 ^pi'ous. iif whioh forty-oiglit ar(> ptlti'v|HHls, ono luiniliod aro i^asl ropods, tl\roo arc 

 !*i'apl»o|>«Hls, ono is* an ooliino«i»-ini. ami ono is a onistnooan. It is similar to tho 

 nppor fanna of iho San IVdro hlnlT, with tho oxooption that it affords a few spocics 

 oonimon in tho lowor San IVilro sorios that aro not fonml in llio np|)or hods at any 

 othor looality. Anothor noliooahlo faot is tho jjroat propondonmoo in nnmhoi-s of 

 gastropods tivor polooypods. Tho fanna sooms to ho that of a rooky hoaeh. 



All ahiii); tho oliff, from t'nnvlish (loori^o's to 'rimm's I'oint, tho jinuol lios 

 nnoonformahly in disoonnoolod massos on tho Miocene shalo. and is covered by soil 

 vary inn in depth from three to ton foot. Krom Timm's Point to tho north alonj; the 

 hhilT this formation is not oxpivsod nntil a point is roachod a little north of tho rail- 

 way ont. lloro tho typical ^nivol of tho nppor San IVdro sorios rests nnoonformahly 

 upon tho lower San IVdm .Ui'ay sjuid. anil is overlain hy a layer of soil. Tho 

 upper San IVvlro cntvol (.see iliagnim IK Plate XXI I) ap;;\in outcrops in the bluff 

 north of tho San Podn> Valley, hut is covered in this bluff by a ?andy stratum 

 between it and the s(»il. This gravel sti-atum runs along the bluff near the surface 

 until it roaches a |HMnt about two hundred yards north of tlie valley, whore it 

 suddenly dips at an angle of -kV for eight feel, resting all the while on the eroded 

 surface of tho lowor Sjui Podn^ strata, .\gain changing its dip to normal, it disap- 

 peai-s uuvlor the detritus at tho mouth oi a short ravine. The unconformable pasition 

 of tho upjH'r gnivel on the lower gn»y sjuul is very apjvjront a few yards south of 

 the n>vino. whore fragments of the lowor San Pedro strata are found in the upper 

 gnnol. .\fter the de|H^sition of tho lower San Pedro bods there came a period of 

 uplift, during which they wore onxlod: then came a period of depression, during 

 which the upper San Pedro bo»ls wore dopivsitod on tho eroded surface ot the 

 lowor wrioss. 



.V heterogenetMJs series of stnita, comjHised of alternating beds of s:uul and 

 gn»vol. ixvur^ aKne tho gnwel stratum at the ravine and to the north of it. 

 These overlying Ivds dip gently to tho north, but the series does not decrease 

 in thickness to the north for the reason that other strata begin near the top of 

 tho blulT. and thus make .1 nearly horizontal surface to the top of the series, which 

 is overlain by .>^m1 to the thickness of from two to ten feet. The lower strata 

 jilong this blull .nro of tine sjind, fi>^iIiferous in places. Near the top of the 

 bluff, however, tho strata ari- comiv-tsed of c«v»rse material, a distinct layer of gravel 

 iHMnontoil with lime and otint.-iining many well preserved fossils forming the top layer. 

 This top stratum first apjH'ars at the top of the bluff about one hundred feet south of 

 tho ravine. Fnim this jviint smith of the ravine it can bo tracovl north along the 

 bluff near tho top. ar\>und tho north end of the bluff, and Ixick agjun on the west side 

 o( this p^»uu^ntory for several hundreii feet. About six feet below the top gravel 

 stnitura is AuotJior layer rich in fossils. The beds below these last two are sand and 

 gr ' ' viition, nearly all. however, fossiliferous. Sv>me of 



ihi . c bedding, while others are horizontal. This alter- 



ualion oi lidding woiild indicate a j>eriod of alternating conditions of elevation and 



