102 



GEOLOGY AND PALAEONTOLOGY. 



Jointing in the Mountain Limestone of the Austwick 

 District.— In respect of the jointing of rocks, the Mountain Limestone district 

 of West Yorkshire is classic ground. Prof. Phillips' observations, published fifty 

 years ago, are still the chief source of information on the subject. The following 

 notes were made last autumn, during a visit to the neighbourhood of Austwick, 

 near Settle. It will be seen that, despite local variations, the joints maybe divided 

 into two sets, A and B, approximately at right angles to one another. The beds 

 are mostly horizontal, or dip at low angles. 



Strike. Distance Apart. Locality. 



A. N. 30 0 or 40 0 W. ) r r. /Bottom of basement conglomerate, Nor- 



B. N. 60° E. .../ 6 1U 10 5 n : \ ber Brow ; beds 2% ft. to 4 ft. thick. 



A. N. 62° W. r. . ■ r. /Upper part of basement conglomerate, 



B. N. 45° E. .../ 2 IC ' 10 4 \ Norber Brow ; beds 1 ft. to 2 ft. thick. 



A. N. 6o° W. lff r • fA -r f fBase of Limestone proper, Norber 



B. N. 30 0 E. .../ ' I Brow ; beds 4 in. to 2 ft. thick. 



A. N. 54° W. ...\ . '« /Limestone, top of Norber Brow: beds 



B. N. 32° E. .../ lrre 2 ular - { 8 in. to 2 ft. thick. 



A. N. 6o° W, ... Limestone, N.E. of Ingleborough Cave. 



B* N* 67 0 fJ 1 ft. to 3 ft. Limestone, E. of Gaping Gill. 



A. N. 43 0 or 50 0 W. \ . fi . ■■ . fi . f Limestone, near Gaping Gill; beds 



B. N. 6o° E. .../ 2 or 4 j 1 ft, or 3 ^t. thick. 



A. N. 55° W. ... 6 in. to 2 ft. ) T . , T , . _ ,. 



B. N. 35 0 E. ... 2 ft. to 3 ft. | Limestone on Moughton Fell. 



The average direction of the A series is thus about N. 50 0 W. ; that of the B 

 series, N. 47 0 E. — Alfred Harker, St. John's College, Cambridge, March 1st, 1886. 



Joints Cutting through Pebbles.— The base of the Mountain Lime- 

 stone in West Yorkshire is often conglomeratic, consisting of a hard limestone 

 matrix, containing pebbles of quartz, slate, and other materials. There may be 

 noticed a peculiarity sometimes seen in other conglomerates. The joints by which 

 the rock is intersected often cut quite cleanly and without interruption through the 

 included pebbles, even those of quartz. This is well seen on a joint-face that has 

 been weathered, the pebbles standing out in relief for perhaps half an inch, but all cut 

 sharply off at the same level. Good localities for observing these joints are at the 

 mouth of Crummack Dale, just below Norber Brow, where the conglomerate is 

 40 ft. thick ; and higher up the dale, at Crummack Beck Head. We may notice, 

 too, the fact, which is true of many basement conglomerates, that the very base 

 (about 5 ft. at Norber Brow) is often almost or entirely devoid of pebbles. In the 

 Eden Valley there is often a considerable thickness of sandstone without pebbles 

 at the base of the conglomerate which forms the lowest member of the Car- 

 boniferous. — Alfred Harker, St. John's College, Cambridge, March 1st, 18S6. 



Asteracanthus ornatissimus in the Middle Oolites near 

 Malton. — During the past month the members of the geological section of the 

 Malton Naturalists' Society had the pleasure of examining an exceptionally rare 

 fossil. One of the members, a short time ago, had the good fortune to secure a 

 remarkably fine fossil spine, supposed to belong to the dorsal fin of an ancient Shark. 

 This peculiar form was described some years ago by Prof. Agassiz, and named by him 

 Asteracanthus ornatissimus. The principal source from which they have been 

 derived is the formation known as the Kimmeridge Clay in the Upper Oolites. 

 This is the only authenticated specimen that has ever been found so low down in 

 the Middle Oolites before in England. Mr. W. H. Hudleston, F.R.S., F.G.S., 

 in a paper read before the Geologists' Association in 1878, mentions the fact of 

 having a specimen in his collection, which he queries as from the Lower Calcareous 

 Grit, but there being no locality, it is open to doubt as to where it came from. 

 The specimen found here has just been presented to the Society's museum. It is 

 as near perfect as possible, showing a very fine section of the tubercles and hooked 

 barks on the lateral surface. It will materially help to enhance the value of the 

 already very complete collection of fossils gathered from the Middle Oolites of this 



neighbourhood. — S. Chadwick, Norton, Malton, May 5th, 1885. 



Naturalist, 



