AN INQUIRY AS TO A SPECIES OF FLY. 177 



says Lyell, "the Scotch Geologist took his two distinguished pupils, Playfair 

 and Sir James Hall, to "the cliffs on the east coast of Scotland, near the village 

 of Ejemouth, not far from St. Abb's Head, where the Schists of the Lam- 

 mermuir range are undermined and dissected by the sea. Here the curved 

 and vertical strata, which are of Silurian age, and which often exhibit a 

 ripple-marked surface, are well exposed at the headland called Siccar Point, 

 penetrating with their edges into the incumbent beds of slightly inclined 

 Sandstone, in which large pieces of the Schist, some round and others angular, 

 are united by an arenaceous cement. ^VVhat clearer evidence,' exclaims 

 Playftiir, ^could we have had of the different formations of these rocks, and 

 of the long interval which separated their formation, had we actually seen 

 them emerging from the bosom of the deep? We felt ourselves neces.sarily 

 carried back to the time when the Schist on which we stood was yet at 

 the bottom of the sea, and when the Sandstone before us was only beginning 

 to be deposited in the shape of sand or mud, from the waters of a superin- 

 cumbent ocean. An epoch still more remote presented itself when even the 

 most ancient of these rocks, instead of standing upright in vertical beds, lay 

 in horizontal planes at the bottom of the sea, and was not yet disturbed by 

 that immeasurable force which has burst asunder the solid pavement of the 

 globe. Revolutions still more remote appeared in the distance of this extra- 

 ordinary perspective. The mind seemed to grow giddy by looking so far 

 into the abyss of time; and while we listened with earnestness and admiration 

 to the philosopher who was now unfolding to us the order and series of these 

 wonderful events, we became sensible how much farther reason may sometimes 

 go than imagination can venture to follow.' "'"-^ 



(To he coutinwd.) 



AN INQUIRY AS TO A SPECIES OF FLY. 



15V J. C. DALE, ESQ. 



I SEND you extracts out of Ray and Moufet, and also from a letter from 

 the son of Dr. Paris to Mr. Curtis. I showed it to Mr. Haliday, and spoke of 

 it to IMr. Spenee; neither could make it out, and wished me to go to Hin- 

 kleshaugh myself and try to get a specimen. I will give Mr. Paris's first. — 

 "I also wanted to ask you the name of an insect which bothered me occasion- 

 ally when I wanted to be quiet and enjoy a fine view, but unfortunately I 

 neglected to procure a specimen, and unless you happen to have visited the 

 spots they haunt, my description will not be sufficient. On the summits of 

 the Dartmoor tors, not only on the highest rock, I was always assailed by 

 a multitude of flies, bearing a resemhlaiice to the hee, (but not what we used 

 at school to call "darting flies,") which came by two or three, increasing in 

 number every moment, flying and buzzing in my face, until I was forced to 



* The reader is refencd to the frontispiece of the last edition of Lyell's "Elements of Geology," 

 for a view and explanation of this interesting: spot. 



VOL. II. 2 A 



