Dr. FiTTON on the Strata below the Chalk. 



221 



barrow Bay ; and in the Isle of Purbeck, beneath Wor- 

 barrow Knob. In the loftier cliffs at Gad Cliff" it is not 

 accessible ; but among the fallen ruins on the shore were 

 some portions of silicified trunks. Between Tillywhim 

 and Durlstone Head a cavity can be perceived in some 

 places, in the part of the cliff" where this bed might be 

 expected. 



Petrified Trees. — The portion of the trees left standing 

 above the dirt-bed in Portland, is frequently more than 

 three feet in height : and one instance was mentioned to 

 me in which six feet of a trunk stood thus in the up- 

 ri<'ht position. I did not see any case in which the roots 

 penetrated into the Cap below ; but observed several fis- 

 sures in the top of that bed, some of them coated with a 

 crust of stalactitic carbonate of lime. In one instance a 

 prolonged branch of the root had evidently been bent out 

 of its course by meeting the Cap, and was continued ho- 

 rizontally along its surface for several inches : the quarry - 

 men said that such cases were not uncommon, and that 

 the roots sometimes ran along the top to a much greater 

 distance, but never penetrated the Cap itself. 



Some very fine specimens of the silicified trunks had 

 been found not long before I saw them ; one of which had 

 been judiciously restored, by joining the fragments and 

 placing the whole erect against the wall of a house. The 

 total height from one extremity to the other was above 

 20^ feet ; the diameter of the stem where the roots went 

 off", about 11^ inches. The trunk was nearly straight and 

 undivided for about 17 feet, and the branches slight in 

 comparison with the main stem. 



A still finer specimen, found, I believe, near the same 

 place, in Dungeness Quarry, and at the same time with 

 that just described, has been brought to London for sale; 

 and I am enabled, through the favour of Mr. Freeman, in 

 one of whose warehouses the specimen was deposited, to 

 insert a representation of it, from a drawing made by Mr. 

 Sowerby, after careful admeasurement, as it lay horizon- 

 tally, the fragments which had been separated appearing 

 to fit exactly. The total length, from the extremity of the 

 roots to that of the branches, was about 23^ feet, and to 

 the bifurcation nearly 20 feet. The roots and undivided 

 portion of the stem to the first crack, occupied about 2 

 feet. The situation of the other cracks, of which there 

 are fourteen or fifteen, is expressed in the figure. The 

 trunk is compressed throughout ; the branch on the right, 

 especially, having been much flattened near its extremity. 



Feet 

 24 



-22 



20 



-18 



16 



14 



12 



10 



-6 



LO 



