18 Mr. W. Pengelly on the Red Sandstones, 
Devonian trilobite Trimerocephalus Icevis.--- Greenstone, apparently 
intrusive, occurs mixed up with the slates and limestones of 
Babbacombe within a stone's-throw of the great "fault" at 
Oddicombe, where the Devonian and Triassic rocks abut against 
each other, as described in my former lecture (see Fig. 3, in 
Transactions " for 1861-2). I have searched frequently, and with 
care, for a Greenstone pebble amongst the conglomerated materials 
there, and have endeavoured to bear in mind the great changes which 
this rock undergoes under atmospheric exposure, but I have never 
detected anything which it seemed possible to refer to the 
neighbouring Greenstone. 
Fragments of quartz are by no means rare ; many of them 
upwards of six inches in mean diameter. Veins of this mineral are 
more or less numerous in the Devonian slates of the county, and 
were probably the source whence those nodules were derived. 
The Conglomerate outlier at Thurlestone, in Bigbury Bay, consists 
mainly, if not exclusively, of detritus of the crystalline schists 
which occupy the southern angle of Devonshire, from the Start 
Point to the Bolt Tail ; the latter being about a mile East of 
Thurlestone. 
Perhaps the most interesting objects found in the Conglomerate 
are the Beehites, so named from the late Dr. Beeke, Dean of Bristol, 
by whom they are believed to have been first publicly noticed. 
Without being closely examined they would probably be confounded 
with the pebbles with which they are associated, and which they re- 
semble in form and dimensions. They vary from half-an-inch to a 
foot in mean diameter ; but these extremes of size are not frequent, 
the more common dimensions being from three to six inches. 
Their surfaces are covered with Chalcedony, generally arranged in 
tubercles, each of which is not unfrequently surrounded with one or 
more rings, and occasionally the same ring invests two or more 
tubercles. The latter vary in size from that of a small pin's head to 
an average pea. In some specimens the Chalcedony seems to be ar- 
ranged on two different types, or, more correctly, the same type on 
two different scales. 
When broken, the interior of the Beekite is found to be Calcareous. 
In most instances the nucleus is only partially attached to the crust 
of chalcedony, sometimes it is completely detached and rolls about 
within the cavity when shaken ; not unfrequently it is reduced to a 
dark-brown, iron-grey, or almost white powder, which effervesces in 
acids. A similar powder surrounds decomposing, fossiliferous, cal- 
careous nodules in certain limestone rocks, as may be well seen in 
Woolborough quarry, near Newton Abbot. Occasionally only a few 
grains of matter remain within the crust, in which case, as might be 
expected, the Beekite is so light as to float in water. 
* " Geologist," vol. iv, page 343. 
