1.54 



THE GEOLOGIST. 



what Mr. Selwyn has advanced ; but the last ground I worked in on that lead 

 being the outermost, or nearest the side of the lead, I again sunk through the 

 black drift, here twenty-five feet thick, containing blackened wood and the 

 cones of the "honeysuckle" (Bantna), and "bottomed" in a stratum of stiff 

 bluish-grey clay, with very large boulders, which stratum was four feet thick. 

 I expect the Spring Gully black drift and the drift of the black lead are of the 

 same age, as the Spring Gully course has been traced to within a short dis- 

 tance of the black lead, which I conceive to have been the main watercourse of 

 tliat period ; indeed, the number of smaller tributary leads of dark colour join- 

 in"- it, in the same way that small streams now fall into larger ones, would in- 

 dicate that such was' the case. Here also the course of dark drift may be 

 easily traced by the black heaps at the surface in striking contrast to the heaps 

 on each side. In following down the black lead we reach Slaughteryard Hill, 

 where the evidence at first may not appear so conclusive, but where, if the 

 facts are carefully weighed, they will I thinly, be found to support the former. 



Standing on the level of the present Cress wick Creek, looking north north- 

 west, Slaughteryard Hill presents a steep escarpment of basalt, which has pro- 

 bably come from the north, as northward the basaltic plateau extends some 

 mile's. Southward it does not exceed two hundred yards, thiiming out very 

 rapidly. Within one hundred and fifty yards are thi'ee leads — the eastern, 

 called the black ; the middle, known as the white ; and the western lead the 

 red streak — as far as had been determined at the time I left (1857) running 

 parallel ; all three running from south to north ; all three overflowed by the 

 basalt; and all three above one hundred feet deep; the deepest being the 

 western, i. e., the red streak. 



Supposing, for the sake of argument, that tlie black, which is also the 

 shallowest, is the oldest, we have a period no doubt, judging from the thick- 

 ness of the deposit (twenty-five feet), extending over a considerable time, cha- 

 racterized, it would appear from the vegetable remains, by extensive and long- 

 continued conflagrations, succeeded by others, in which the utter absence of all 

 igneous appearances prevails, succeeded in turn by an igneous outburst, cover- 

 ing many square miles, with a basaltic overflow. On the other hand, take as 

 the oldest the red streak- — the deepest first, the white follows under certain 

 modifications ; then, when we reach the period of the black drift, and igneous 

 forces come into operation, it does not call for a great stretch of imagination to 

 suppose that the period was consummated by a grand outbui'st and overflow of 

 basalt. I am aware that in " Siluria," p. 493, Sir R. Murchison and others 

 account for the charred appearance of the vegetable matter, by showing that 

 such matter is charred and destroyed in situ by the basalt; however true that 

 may be in other cases, I venture to think that had those eminent geologists 

 seen tlie vegetable matter in Spring Gully, where there is no basalt, or other 

 igucous rock, or the evidence that there ever had been such, they woidd have 

 seen the inapplicability of the reasoning in this instance. The black lead also is 

 black a groat way above, tkat is, much further south than the basalt. In 

 writing the above I do not impugn the accuracy of the observations made by 

 ]\lr. Selwyn and others, I simply desire to record wliat I myself observed in 

 the localities I speak of. I never worked elsewhere, and therefore tliese de- 

 tails are purely local ; still, if true, the stratum containing the vegetable matter 

 is not the oldest. — I am, sir, yoiu's truly, J. jMorgan, Carmarthen. 



