74 John Parkinson— Rocks of Northern Guernsey. 
In the Horton district we appear to have a normal succession. On 
Ingleborough, above the Caninia basement bed Sz is represented by the 
Bellerophon bed with Nematophyllum minus, and is in all respects 
similar to the same zone on Scout Scar, Hampsfield Fell, ete. Above 
these, beds rich in Chonetes papilionaceus, Lithostrotion Portlocki, and 
Alveolites septosa succeed, and corals allied to Dibunophyllum @ are not 
uncommon still higher with characteristic Producti. But I do not 
know of the occurrence of Lonsdaleia floriformis or Productus giganteus 
on Ingleborough. On Penygent, however, at Hunt Pot, we have a rich 
fauna of upper Dibunophyllum age containing, beside the typical 
Productus giganteus, Lonsdaleia floriformis, Dibunophyllum aft. , 
Lithostrotion junceum, etc. In the lower shale band a Spiriferina 
closely related to cctoplicata is common, and Dr. Vaughan tells me 
that he has lately traced Sowerby’s type-specimen of Spirzferina 
octoplicata to an horizon which appears to be Dp, the identical horizon 
of the Hunt Pot Beds. 
The bed above this on Penygent is frequently crowded with 
Productus latissimus and thick reefs of Dibunophyllum in the y- stage, 
a form which appears to be larger and longer than the typical 
examples. This bed is represented on Ingleborough by the cement- 
stone bed seen in the swallowhole dedicated in the Ordnance map to. 
Tatham’s wife, and is also found at Riblehead. The same zone occurs. 
in the Wensley Dale district at the top of the Hardraw Scar Limestone, 
while the bottom of that bed is full of typical Productus giganteus. 
The highest zone in the district, that contained in the Upper Scar 
Limestone, shows a further modification of the giant Producti to 
a form which, some years ago, I tentatively referred to the variety 
Edelburgense.' 
IV.—Tue Rocks or NortuErn Gurrnsey. 
By Joun Parkinson. 
Introduction. 
[* a communication to the Geological Society in 1900 I had 
occasion to compare the rocks of the south-eastern coast of 
Jersey with the hornblende gabbro, diorites, and granites of 
Northern Guernsey; and to point out that in general terms the 
petrographical types of the two islands bore a close resemblance 
to each other, group for group, in sequence and general relations. 
Since work abroad renders it improbable that I shall be able to 
devote much additional time to this subject, the following notes are 
given as a possible aid to future observers. 
The very valuable work of the Rev. Edwin Hill? in this island 
renders superfluous any lengthy note on general characters ; suffice 
it to say that the southern part of the island consists of gneiss with 
a few intrusive masses and dykes; the northern of diorites and 
intrusive granites, except for an oblong area on the eastern coast, 
' T here limit the term giganteus to the large coarse-ribbed forms found, as far as 
I am aware, only in the Dibunophyllwm zone, and usually confined to the upper part 
of that zone. 
2 Quart. Journ. Geol. Soc., vol. xl (1884), p. 404 and map. 
