390 Mackintosh — Ralkvay Geology in Devon. 



to the bivalve Crustaceans just named or to some of the Lamelli- 

 branch moHusca. The Entomostracans, Beyrichia arcuata, Bean, and 

 Gythere fabulina, Jones and Kirkby, also occur, together with a few 

 fish remains, a few stray Anthracoptera, and some fragments of plants. 



EXPLANATION OP PLATE XVIL -FIGURES 6-8. 



Figs. 6 and 7.* Portions of the fore-wing or tegmina of an Orthopterous insect nearly 

 allied to Blatta or cockroach. From the Coal-measure opposite Claxheugh, 

 near Sunderland. 

 „ 8. Part of an Orthopterous insect, apparently the abortive anterior wing of a 

 species related to the Phasmidce. From the same locality as the last. 

 * The original of Fig. 7 is in the collection of W. M. Wake, of Sunderland. 



III. — ^Eailwat GEOLoax, No. I. — From Exeter to Newton-Bushell 



ANB MoRETONHAMPSTEAD. 



By D. Mackintosh, F.G.S. 



(PLATE XVIII.) 



THE district selected for this article embraces a very unusual 

 variety of geological phenomena, consisting of different kinds 

 of recent gravels and Tertiary deposits, Greensand table-lands and 

 patches, Triassic sandstone and conglomerate, rocks belonging to the 

 interval between the Trias and uppermost Silurian strata, trap, 

 and granite. 



From Exeter to Starcross the valley of the Exe widens into a 

 plain, part of which is permanently occupied by the sea, the other 

 part showing signs of an "unlimited liability to liquidation" 

 during high tides and floods. On the right hand, at intervals, may 

 be noticed a terrace of gravel. Near Alphington it is from ten to 

 twelve feet thick, thinning out hill-wards. It consists of rounded 

 fragments of carbonaceous grit, trap, Blackdown flints, etc., with 

 lenticular patches of finer shingle, clay and sand, the latter some- 

 times exhibiting oblique lamination. Between Starcross and Daw- 

 lish the sea-beach is the most interesting phenomenon. During 

 south-east winds the shingle is there thrown up against the railway 

 wall to a thickness of many feet in the course of a few hours. In 

 some places the shingle may be seen arranged in successive terraces 

 corresponding to different tidal levels. At some height above the 

 level of the railway, there are several fine sections of a gravel- 

 covered old ocean-bed, commonly called a " raised beach. " 



From Dawlish to Teignmoulh. — The railway here runs under a cliff 

 of Triassic sandstone and conglomerate. The sea has left stacks and 

 pillars, and hoUowed-out recesses. The " Parson and Clerk" rock (seen 

 best on looking northwards from near Teignmouth) is a fine speci- 

 men of an arched buttress with an adjacent slender column. The cliff, 

 in places, has given way to gravitation, assisted by rain and frost, so 

 as to originate combe-shaped hollows similar to many in neighbour- 

 ing inland districts. Ee-assorted pebble-beds may be traced on the 

 top of the cliffs, but it is difficult to distinguish them from beds 

 in situ unless where they fill up denuded hollows, or contain chalk 



