EOCENE MARL. 453 



and thickest at the north-eastern, Neston and Evelynton. At 

 Coggins Point, where traced along the face of the river cliff con- 

 tinuously for more than half a mile, it is usually 6 feet thick, 

 never more than 8, and never less than 4 feet, except where 

 terminating. The general and almost uniform colour is a pale 

 dingy yellow. The few shells remaining are not perceptible with- 

 out careful observation, and the whole mass, when dug down for 

 use, is scarcely distinguishable from many common and barren 

 sub-soils, or clay river cliffs, of like colour. Two thin but con- 

 tinuous and separate layers of almost stony hardness extend 

 through the whole bed. These contain from 85 to 90 per cent, 

 of carbonate of lime, and may be burnt to excellent quick-lime 

 for cement. The marl intervening with these hard layers is simi- 

 lar to them in colour and general appearance ; but is quite soft and 

 mellow in handling, and in that respect differs from all other known 

 marls. The very uniform calcareous proportion of this part is 

 about 53 per cent.; and taking an equal section of the whole 

 thickness of the bed, and with the greatest care to obtain a fair 

 average sample, the strength in carbonate of lime was found to be 

 62 per cent. This is far less of calcareous matter than is con- 

 tained by many miocene marls which show less effect than this as 

 manure. But besides its calcareous matter, this eocene marl has 

 some little gypsum, some kind of saline matter which cattle are 

 fond of licking (believed to be sulphate of alumina) and some 

 amount of the granules of " green-sand" and more of this than 

 most of -the miocene marls. The other earth of this marl is mostly 

 of yellowish clay, and composed more of argillaceous than sili- 

 cious matter. I confess that all these additional ingredients, toge- 

 gether, do not seem to me sufficient to account for the superiority 

 which this marl exhibits as manure. 



Though this peculiar kind of marl was so early known, and its 

 value appreciated, and, though it underlies the whole of Coggins 

 Point, yet it is covered there so deeply by the overlying earth, and 

 is therefore so difficult to work extensively, and, moreover, is so 

 distant from the main body of the farm, that this has not been 

 applied to more than 65 acres, out of some 700 marled on that 

 farm. Other proprietors have elsewhere made much more extensive 

 applications of this marl. The peculiar effects of this kind of marl 

 were tested with the most accuracy by Messrs. Collier H. Minge, 

 then of Walnut Hill, and Hill Carter, of Shirley ; both of whom 

 used this marl from Coggins Point, water-borne to distances of 

 twelve and fifteen miles. Though the marl was given to them (in. 

 the bed), it was yet very costly in the labour of digging and trans- 

 portation; and therefore they used it with strict economy, and 

 carefully estimated the results. But highly as they both thought 



