J. S. GARDNER OH THE LOWER LONDON TERTIAE1ES. 203 



wich, are comprised in this section ; but, owing to extensive tracts 

 being sometimes laid bare at low water at Peculvers, the upper beds 

 can usually be more profitably studied there. The line of concre- 

 tions is a marked feature in the cliffs as they rise at Reculvers. 

 Below them about 12 feet of compact yellowish slightly argillaceous 

 sand, darkening when exposed to the sea and highly fossiliferous, 

 forms the base of the cliff. The cliffs at first trend W. by N., and 

 the strata are horizontal, but gradually dip about 2° W. Beyond 

 the point to Bishojjstone Gap the cliffs are in a more south-westerly 

 direction, and the dip is maintained at from 2° to 3° ; but up the 

 chines the strata show horizontal where the face rakes S.W. by S. 

 Prom the bottom of the bay the cliffs trend slightly W. by N. and 

 the dip is again 1° to 2° W. 



These sands are quartzose, somewhat micaceous and argillaceous, 

 with green grains ; ferruginous concretions are common in them, in 

 one of which Mr. Prestwich found the cast of a most interesting 

 pine-cone. Pieces of unrolled silicified wood are not uncommon ; and 

 one of these proved to be the magnificently preserved stem of 

 Osmunda Dowkeri so accurately described and figured by Mr. Car- 

 ruthers. The Mollusca are abundant, but of few species, almost 

 wholly bivalves. By far the most abundant form is Thracia oblata, 

 imbedded flat, with the two valves closed tightly. The next most 

 abundant forms are Pholadomya Koninckii, which always occurs in 

 an upright position, and Cyprina Morrisii. (Among the rarer forms 

 from the Thanet Beds are several species of Nucula, some of which 

 occur only at Pegwell Bay.) The only univalves that my brother, 

 Mr. E. T. Gardner, P.L.S., who has diligently searched, and myself 

 have met with, are a JSlatica and an Aporrliais with a scalaria-like 

 spire, and a Mureoc, though some others are recorded by the Survey. 

 These were evidently deposited in water at a depth beyond the 

 reach of the waves, as there are few broken or even separate valves 

 of shells, and the wood is unrolled, while this and the fir-cone and 

 fern-stem show that they were not wholly beyond the influence of 

 estuary water. They contain hardly any vertebrate or crustacean 

 remains, so far as is yet known. Their deposition was probably not 

 very dissimilar to that of some of the sediments forming on the chalk 

 on the same coast at the present day. 



At the point the concretions are 6 feet above the beach, and they 

 and the sand below them are crowded with Cyprina : 200 yards east 

 the concretions are overlain by some 12 feet of looser pale grey 

 mottled and piped sand, on which rests a bed with silicified Corbula 

 regidbiensis, ' a bed traceable from this point to Bishopstone Gap, 

 on the west side of which it appears on the beach below high-water 

 mark. It is valuable as the ouly land-mark by which the division 

 between the so-called Thanel and Woolwich-and-Pueading Beds can 

 be readily picked up in the cliffs. 70 yards west a small chine occurs 

 (fig. 6) ; and the concretions disappear at the base of the cliffs, but 

 form a well-marked line of rocks cutting diagonally across the 

 flats at low water, in a westerly direction. At another 250 yards 

 west the beds at the base of the cliff are mottled with bright orange ; 



