Freestone Quarries of the Isle of Portland. 99 



ft. in. 



1. Soil . - - - 



2. ' Rubble ' - - - 



3. * Blue clay » 



4. ' Slate ' [This bed is used for roofing houses and walls* 



for which purpose it is an excellent and 

 durable material] 



5. A layer of reddish-brown clay - 



6. f Bacon tier ' 



7. A layer of blackish-brown clay - - 



8. « Ash * 



9. Ash burr, or soft burr - 

 10. < Dirt-bed ' 



Total - - - - 



These beds vary considerably in thickness at different 

 places, owing to the strata in many parts being, as above 

 stated, so very much dislocated : in some places they are so 

 disturbed and broken, that the measurement varies every foot ; 

 in other places, however, as where my measurements were 

 made, they are only slightly inclined (having neither compass 

 nor clinometer with me, I could not learn in what direction, 

 or at what angle) ; and in a few places, Fern Street Quarry, 

 for example, these beds are almost, if not perfectly, horizontal. 

 The " dirt-bed " consists of a black rich-looking mould, con- 

 taining, like the surface, a great many white-coloured water- 

 worn stones ; and in it, and upon it, are found the remains 

 of groves of palms and other trees allied to the modern genera 

 Zamia and Cycas, now only flourishing in warm climates, 

 evidently standing on the very spot in the dark-stained soil 

 in which they originally grew. These trees are tolerably 

 abundant, and their remains are scattered, more or less, over 

 the whole quarry ; some of the trunks lie prostrate on the 

 ground, many are inclined at various angles, and some few 

 stand perfectly upright, their roots firmly fixed in the " dirt- 

 bed," and their stems and branches stretching upwards 

 through the " soft burr " and " ash " above. They seldom, 

 however, when so situated, exceed 3 ft. or 4 ft. in height. One 

 of these trees, I particularly noticed in this quarry ; it was 

 inclined at a slight angle, about 3 J ft. high, was only half ex- 

 cavated, the other half being imbedded in the limestone 

 (which, adjoining this wood, is uncommonly hard, much more 

 so than in other places, owing to the presence of flint derived 

 from the silicified trunks), and must have measured at least 

 9 ft. in circumference, and the quarrymen assured me that 

 some are found from 1 2 ft. to 1 5 ft. in circumference. Of 

 this petrified wood very good whetstones, for sharpening 

 knives and razors, are fabricated by the workmen. 



