SS BRYOLOGY OF THE YORKSHIRE OOLITE. [February, 



The district which comes within the compass of our remarks 

 is all comprised within the limits of the North Riding. It is 

 estimated that in North Yorkshire the Upper Oolitic strata 

 cover an area of about 200 square miles^ and the Lower Oolitic 

 and Lias of about 650, this of course including the Liasic for- 

 matioQS of the vales of Mowbray and Cleveland. The Oolitic 

 moorlands, of the muscology of which only we purpose treating, 

 extend north to the sea, beginning to margin the coast about 

 Saltburn, from whence to Filey they form irregular cliffs, vary- 

 ing considerably in elevation, but generally about 120 or 130 

 feet ; the highest point which they attain being at Boulby, which 

 is nearly 680 feet above the sea-level. Inland, they sink into 

 the vale of Cleveland, and extend west as far as the vale of 

 Mowbray, and to the vale of Pickering on the south, their 

 western boundary being marked by a series of abrupt descents, 

 forming rugged and irregular scars. 



Two distinct ranges of hills may be traced, differing from one 

 another alike in physical configuration and lithology : the first 

 and most northern, those of the Lower Oolite, which reach 

 from Osmotherly Bank to the peak culminating in Burton 

 Head, a series of undulated moorlands made up mostly of sand- 

 stone; the second and most southern, a series of tabular cal- 

 careous plateaux, extending and sinking in level gradually 

 from Hambleton End, eastward to the Castle Hill at Scar- 

 borough. 



The Lower Oolite range of moors is watered for the most part 

 by tlie Esk, and those of the Upper Oolite by the Derwent, 

 the tributaries of which drain innumerable picturesque dales 

 and gills, often with precipitous, rocky, and more or less 

 wooded banks. The principal dales drained by the Esk are 

 Kildale, Baysdale, Danbydale, Glazedale and Goathlandale, and 

 the highest point attained by the Lower Oolite is 1485 feet at 

 Burton Head. The dales of the Derwent are Bilsdale, Brans- 

 dale, Farndale, Rosedale and Newtondale, which at their sources 

 are in a great measure composed of Lower, and the lower parts, 

 of Upper Oolite. 1300 feet, at Hambleton End, is the highest 

 point which the Upper Oolite reaches. 



The same peculiarity of two distinct ranges extends into a 

 subordinate set of hills, known as the Howardian range, but 

 the distinction of the muscology of the two is here marked in 



