6 The Marchioness of Hastings on the Tertiary Beds 



on exposure to the air it becomes friable and quickly falls into 

 pieces. 



Stratum 9 is about 6 feet in thickness. It commences with a 

 very narrow band of lignite ; after which is a band of clay, green 

 mottled with iron, through the base of which passes a band of 

 ironstones of about 10 inches in thickness which project from 

 the cliff. Under this band appears occasionally a narrow seam 

 of limestone, succeeded by a narrow band of green clay, con- 

 taining Paludina and Potamomya very much crushed. No 

 other remains or shells are found here. There is an idea prevalent 

 that the ironstones which run through this bed are the result of 

 exposure to the atmosphere. This is utterly fallacious ; I myself 

 have seen this layer of ironstone uncovered in a horizontal direc- 

 tion for 8 feet beneath the surface, finding them there in the 

 condition precisely as at their first appearance on the face of the 

 cliff. Generally they occur in a regular line, extending hori- 

 zontally in large masses of many feet, but sometimes they are 

 replaced by the clay. 



Stratum 10 averages from 8 to 9 feet. It consists of fine white 

 sand traversed with bands of gray marl. The centre of the bed is 

 nearly pure white sand. The gray seams of marl prevail at the 

 top and at the base, which consists of them principally, and 

 which is about 2 or 3 feet in depth. 



The whole of this stratum contains seams of Limnea, Po- 

 tamides, and Melania ; but the lower part contains beds, barely 

 an inch apart, of Potamomya angulata, with innumerable seeds 

 of Char a and Serpula tenuis (found only in this stratum), 

 which flake off in large masses after any portion of the stratum 

 has fallen. About 3 feet from the top is where the animal 

 remains are principally to be met with, immediately under the 

 gray bands which traverse the upper part of the bed. Asso- 

 ciated with them are Potamides, Planorbis euomphalus, Limnea, 

 Potamomya, Dreissena Brardii, and Paludina lenta. This and 

 strata 5 and 11 are the only beds where the first mention of 

 these shells is found, except very sparingly, and stratum 10 is 

 the only one where they are found in any abundance. They 

 invariably accompany animal remains, and whenever they arc 

 found we know bones are near. The sand immediately sur- 

 rounding the bones becomes of a greenish, dirty, clayey nature, 

 giving evidence of decomposed animal matter. It is rare to 

 find these remains near the commencement or end of the bed. 

 The middle, a little to the west of Hordwell House (Dr. Cham- 

 bers's), is the locality which I have found the most productive. 

 Unfortunately, the time of our British Cuvier — Professor Owen — 

 is so much occupied, that many of the species found here are 

 undescribed; I can only give a general idea therefore of its 



