MAGAZINE OF SCIENCE AND ART. 
135 
simultaneously the superior maxillary and palatine 
bones. 
Lastly, we may surmise, though this has not yet 
been fully proved, that the venom and salivary 
glands are similar in their structure. 
Consideration of these points has led me to the 
following conclusions:— 
First,—That although certain snakes may possess 
a power of rendering their fangs somewhat more 
perpendicular; such is certainly not the case in the 
most venomous varieties. 
Second,—That in no instance do the poison fangs 
become so much retracted within their membraneous 
beds, or assume so horizontal a position, as to ren¬ 
der them incapable of entering substances contained 
between the jaws, when these are pressed together. 
I am further led to suppose that the primary ob¬ 
ject of the so-called poison apparatus is that of 
assisting in digestion, in the fulfilment of which 
purpose, the fang is in constant use, during the 
process of swallowing the prey; and that in the 
less venomous varieties this is less necessary, and 
less provided for, in consequence of the presence 
of a greater or less number of teeth in the superior 
maxillary hone. 
I have to crave the indulgence of my hearers, for 
the serious imperfections which 1 am aware exist in 
the foregoing pages ; and, in apology, to state, that 
the present is the first instance in which l have de¬ 
viated from the especial path of professional obser¬ 
vation ; and that the dissections, necessarily minute 
as they have been, were prosecuted in moments 
snatched from the duties of my practice. 
(To be continued.) 
[The author requests us to mention that he will be 
glad to receive specimens of serpents from any part of 
the colony, alive and uninjured, where possible.] 
CORRESPONDENCE. 
We have been favoured by a correspon¬ 
dent at Duntroon, near Queanbeyan, with 
an interesting collection of fossils'gathered 
in his immediate neighbourhood. They 
were accompanied with the folio wing me¬ 
moranda, which we reprint, together with 
the observations thereon, by that eminent 
authority the Rev. W. B. Clarke, F.G.S., 
&c. &c. 
We are induced to do this, in order to 
stimulate other gentlemen residing in re¬ 
mote districts in the interior, to forward 
geological specimens, or illustrations of 
natural history that may surround them. 
We shall in all cases endeavour to obtain 
a first-rate opinion upon them, and where 
the information contained is valuable, we 
shall print it in our correspondence 
columns. 
To the Editor of the Sydney Magazine of Science 
and Arts. 
Duntroon, Queanbeyan, 
_ 2nd September, 1857- 
Dear Sir,—An opportunity, having presented itself 
for sending a small parcel to Sydney, I hope you will 
accept the accompanying geological specimens. 
So far as I can judge, the fossil remains are of pecu- 
Nov. 1857. No. (). 
liar interest, being types of the earliest inhabitants of 
the globe, and apparently analogues of European genera. 
1 am not aware of any similar specimens having been 
discovered in Aus-ralia, but it is possible 1 may be in 
error. 
Tliey may be thus classified :— 
1. Shale. (Micaceous, and finely laminated.) 
2 Calcareous Grit, forming the base of the Silurian 
system, and similar to the Potsdam Sandstone of the 
United States, in which the earliest fossilised remains 
are discovered. 
3. Subcrystalline limestone (analogous to the Aymes- 
bury limestone),which contains shells of the Pentamerus; 
a specimen of which 1 have found, not in this forma¬ 
tion, hut in an argillaceous limestone in the neigh¬ 
bourhood. 
4. Petrified wood. 
5. Statuan%or saccharine limestone, non-fossiliferou*. 
The remaining specimens aro all taken from the same 
formation, which appears to be identical with the clay 
slate ot the lower Silurian. The fossil shells are prin¬ 
cipally Brachiopodous molluscs, as shewn by the 
numerous impressions of A frypa, Pentamerus, Or this 
7erebratula,and that singular crustacean, the Trilobite. 
The stratum from which they wore procured is drilled 
in some parts with perforating mollusca, and contain* 
quantities of Tentaeulites, allied to the class Annelida. 
These specimens may be interesting to you, though 
scarcely worth preservation in a museum. ’ Their prin¬ 
cipal value consists in the light they throw upon tho 
earlv geologic conditions of Australia. Tho existence 
of the oldest sedimentary rocks proves the great anti¬ 
quity ot tho southern continent, and confutes the erro¬ 
neous impression, that the greater portion of tho 
Australian mainland was not elevated above the sea 
anterior to the carboniferous period. The shells of the 
genera Terebratula prove that this must have been a 
deep sea formation. It appears to have been subjected 
to extensive igneous action, and is much fractured and 
contorted, indicating the agency of subterraneous forces, 
in past ages. I remain,* 
Your’s faithfully, 
CHAS. GRANT ROBERTSON. 
SILURIAN FOSSILS. 
Notes on some geological specimens collected by 
Charles Grant Robertson , Esq., of Duntroon , near 
Queanbeyan. 
Dear Sir ,—The specimens submitted to me by 
you, as recently collected by Mr. Robertson, of 
Duntroon, belong to the lower members of what is, 
probably, the equivalent of the Upper Silurian for¬ 
mation of England, and to that position which is 
marked by the IVenlock shale and limestone. 
In the neighbourhood of Duntroon, and for a 
considerable tract of country on each side, extend¬ 
ing, at intervals, throughout the whole region 
between the Coodradigbee river on the west, and 
the Clyde river on the east, I have long ago traced 
the existence of this formation. I am very glad to 
find, that a gentleman of observation and acquire¬ 
ment in geology is engaged in adding to the 
collections which have been already made by others, 
and in endeavouring to extend our knowledge of 
that interesting field which lies around him. 
The specimens before me are, therefore, not the 
first discovery of the kind in Australia. It may be 
satisfactory' to mention some that have preceded. 
The late Sir T. L. Mitchell, in his account of 
“ Expeditions/’ mentions the fact, that corals, 
which were ascertained by Mr. Lonsdale, of the 
Geological Society (to whom we are indebted for 
the geological notices in that book), to belong to 
the Wenlock rocks, were collected by him from 
Yass plains. Subsequently, from the same locality 
