114 THE GEOLOGY OF BRIDPORT. 



distinguished by a line of springs, as the clay below is more im- 

 pervious to water than that above, which consists of the Laminated 

 beds (7) we have met before under Golden Cap. Next comes 

 (8) some 70 or 80 feet of yellow micaceous Sands and Clays, 

 which further inland form the sides of the deep lane behind 

 Symondsbury. Inland they are hard to distinguish from the 

 Midford Sands (10), of which we shall speak directly. In the 

 cliff, however, they are distinctly separated by a band of Lias Clay, 

 known as the Upper Lias, here some 70 feet thick. A curious 

 fact is that the Brown Nodular Marlstone which caps the Middle 

 Lias is cemented to a pale cream-coloured and pink Limestone, 

 which forms the base of the Upper Lias, so as to form one single 

 rock bed about 3ft. thick. Fragments of this junction-bed may 

 be found on the shore at the base of the cliff, the lower portion 

 containing several species of Pleurotomaria, together with A. 

 Spinatm and Communis, the upper portion containing A. Bifrons, 

 Serpentinus, and Communis. It is in the Upper Lias beds near 

 Whitby that the jet is found which is so valuable an article of 

 local manufacture. Jet is simply a resinous variety of lignite 

 formed from coniferous wood. I do not know if any specimens 

 have been obtained in this neighbourhood, but it is quite possible 

 they might be. 



Above the Upper Lias in Down Cliff come the Midford Sands 

 (10), and these mark the transition from the Liassic to the 

 Oolitic Epoch, being generally classed now with the latter series. 

 The Palseontological affinities of these sands are, however, not 

 finally determined, and the discovery in them of any new Ammonite 

 would be of real service to the Geological Survey. They are best 

 known to us in the fine perpendicular cliffs to the east of Bridport 

 Harbour, but they largely contribute to much of our local scenery ; 

 the hills from Upper Loders to Chideock being chiefly composed of 

 Midford Sand, while the valleys are Middle Lias. Glastonbury 

 Tor and Brent Knoll are Midford Sand. We may note that the 

 celebrated Ham Hill building stone is Midford Sand, and it is quite 

 possible that in this neighbourhood there are beds of it sufficiently 



