304 J- E. BLAKE AND W. H. HUDLESTON ON 



marked, though probably represented by the extreme top of No. 5, 

 in which Ammonites varicostatus is not rare. 



As we pass onwards to the east, we come to an important quarry 

 in which these lower beds are again well represented, though the 

 arenaceous type of the upper ones is still in the ascendant. This is 

 the quarry near the Lamb Inn, about six miles from Faringdon, 

 described by the Geological Surveyor as being the only indication 

 of Upper Calcareous Grit in the neighbourhood. We will add the 

 names assigned to the various portions to our own description. 



Section at the Quarry near the Lamb Inn, 



ft. in. 



1. Deep-red sandy loam, of varying thickness, unconformable to the 



lower beds, resting in some places on No. 2, and in others on 



No.3 3 



2. Flaggy oolitic sandy limestones, resting on sand with small 



shelly calcareous fragments and Lydian stones 1 3 



3. Siliceous sands (1 ft. 6 in.) graduating into brick-earth clays, 



unconformable to the bed below, which is half cut through in 

 places, and exposes an eroded surface. [Upper Calcareous 

 Grit of Survey.] 7 6 



4. Blue -hearted shelly limestone, partially oolitic, with brashy 



partings. The top is deeply eroded in places, forming pockets. 

 Ammonites plicatilis, Belemnites abbreviatus, Opis Phillipsi, 

 Trigonia perlata, T. Meriani (abundant), Pcma mytiloides, Ger- 

 villia aviculoides, Trichites, sp., Modiola cancellata, Pecten lens, 

 P. qualicosta, P. fibrosus, P. demissus, Hinnites velatus, Echino- 

 brissus scutatus. [Coral Rag, a.] 3 6 



5. Blue pisolite, becoming more shelly below, with fossils similar to 



those of the bed above and Lima rigida. [" Coral Rag, b."] ... 3 6 



6. Blue-hearted intensely hard calcareous grit, graduating down- 



wards into the next. [Lower Calcareous Grit.] 1 ft. 4 in. to 2 



7. Yellow and white sand (base not seen) 7 



The fine fossiliferous bed here seen, which from the abundance of 

 that shell we may call the Trigonia-hed, gives us at once our datum- 

 line in its obvious identity with the shelly beds at Faringdon and 

 High worth ; and thus we see the pisolite below taking the place of 

 the nodule-bed of the former and the Coral-bed of the latter locality — 

 not, be it noted, of the Coral Rag proper of this district, with which 

 it has no relation ; and the passage-bed below is here again slightly 

 marked. 



We learn also something here from the upper beds. One cannot 

 fail to be struck with the remarkable erosion of the top of the 

 calcareous bed, No. 4. Though it may be partially due to subse- 

 quent chemical action on the spot, it is certainly also due to an 

 interval of time between the two deposits. This fact and the 

 graduating upwards of the sands and clays into the red ferruginous 

 earth in some parts of the quarry doubtless induced the Surveyor 

 to map the former as Upper Calcareous Grit, though the lower 

 portion by no means coincides with its character elsewhere ; and the 

 isolated position of the patch, so far from the dip margin of the 

 formation, is apt to attract attention. Having seen the red earth 

 overlain by Kimmeridge Clay at Faringdon, and capping other 



