Earypterid Remains in Carhonifcrous Shales of Scotland. 505 



Second Group in Fireclays and Plant-Beds. 



(1.) Joppa Quarry, 3 miles E. of Edinburgh. — The two 

 positions in this quarry are the most important in this 

 group. These are about 100 feet apart vertically, and are 

 both fireclays beneath small coals each 3 inches in thickness. 

 The lower one lies about a foot below the Joppa limestone, 

 which is well known to be the lowermost of the Upper 

 Limestones, and underneath it lie the valuable seams known 

 as the Edge coals of Midlothian. The section may be de- 

 tailed — Joppa limestoae in two beds, 4 feet; shale, 1 foot; 

 coal, 3 inches; shale and fireclay, 6 inches; then a thick 

 bed of sandstone, the surface of which immediately under 

 the fireclay is traversed by numerous roots and rootlets of 

 Stigmaria. The first 3 inches under the coal is in parts 

 a shale rather than a fireclay, and has in it numerous 

 shreds of the epidermal tissue of plants in a mummified 

 condition, many of which are translucent, and show the 

 structure as well as in recent plants. In many of these 

 shreds the stomata or breathing pores are distinctly visible. 

 A good number of spores occur among the vegetable dShris, 

 a few shreds of scorpion skin, and a great many pieces of 

 Eurypterid skin with all the markings which distinguish 

 the family nearly as perfect as when in life. There is 

 evidence that much of the vegetable debris and also the 

 Eurypterid fragments which the wind wafted about were 

 limed by the waters in the little pools on the surface of an 

 old soil, and when over-saturated sank and were buried with 

 the dust that the same winds carried into the pools from the 

 land surface immediately surrounding. The next position 

 in Joppa quarry is situated in the eastmost face, and the 

 bed they lie in consists of 3 inches of fireclay below 3 inches 

 of coal, and has yielded hundreds of pieces of Eurypterid 

 skin. They are all in exceedingly good condition, with the 

 peculiar ornamentation, the " hall mark " of the family, as 

 emphatically embossed as we see in minted coin or medals. 



(2.) Shear Burn, near Harburn Tile Works, 3 miles S. of 

 West Calder. — Beneath a 2-inch coal occurs a layer of fire- 

 clay equally thin, which has yielded for its thickness an 



