TRANSACTIONS OF THE SECTIONS. ite 
by the fall of the overlying block, that the place each occupied was the upper sur- 
face of the deposit when the block fell, that the deposit was capable of offering a 
firm resistance to a heavy falling mass, and that the Cave-earth was introduced into 
the Cavern successively and at many different times. 
The third class consisted of bones broken with an oblique fracture, and precisely 
resembled the larger remnants left by Hyzenas, as the author had found by a series 
of experiments which he had made at the Zoological Gardens, London. 
The fourth class of bones were those which had been split longitudinally, with a 
fracture more or less clean. Having shown that they were not divided by the 
Carnivora, nor by exposure to the weather, the author proceeded to show experi- 
mentally that Man, with no other tools than such as he could readily have com- 
manded in the Paleolithic age, was perfectly capable of splitting them ; and gave 
it as his opinion that the object was to obtain long laths of bone, for making such 
bone tools as the Cave men are known to have used. 
On the Conchoidal Fracture of Flint as seen on Flint-faced buildings in 
Norwich, Yarmouth, fe. By C. B. Rosz, PGS. Fe. 
On the Crag at Aldeby. By C. B. Rosz, F.G.S. ge. 
Tn the summer of 1865 the author was shown some mammalian bones from a brick- 
yard at Aldeby, near Beccles, but on the Norfolk side of the Waveney. Their colour 
and character indicating the existence of a Crag deposit, the author took an early 
opportunity of examining the spot from whence the bones were taken, and there 
his suspicion was quickly confirmed. After repeated visits to the locality he was 
enabled to give the following section. Beneath the vegetable soil lies a bed of 
coarsish flint gravel, 4 to 6 feet in thickness, followed by sand and shingle 1 to 2 
feet thick. Immediately beneath this lies an excellent brick-earth loam, varying 
in thickness from 3 to 7 feet; this loam encloses a few subangular flints, and no 
other erratic bodies. To the loam succeeds a fine ferruginous sand to the depth of 
6 feet, enclosing an abundance of the usual Upper Crag shells, the majority of the 
bivalves with the valves disunited. At the depth of 3 feet in this sand occurs a 
bed of Mya arenaria of all ages, with their valves united, and in the position in 
which they lived and died. ‘Two separated valves of Mya truncata were only met 
with. It was in the immediate vicinity of this Mya-bed that the fragments of an 
antler of a Cervus was found, and also the vertebra of a small cetacean. 
Cyprina islandica was abundant, but, unlike the Mye, the valves were invariably 
disunited. 
At the depth of 6 feet below the brick-carth is found a bed of shells in which 
Astartes predominated, with both valves united, whereas in the upper bed the valves 
were almost invariably fopnd separated. Here the presence of water put a stop to 
further digging. The author bored beneath the Astarte-bed 8 feet, in a somewhat 
loamy sand with traces of shells. 
In determining to what member of the Crag formation the Aldeby bed belongs, 
the author compared it with the approximating Crag beds of Norfolk, in preference 
to those of Suttolk, and more particularly with the Brammerton Crag (see Richard 
C. Taylov’s section, published in the Geol. Trans. for 1823), a section to be 
depended on. 
ow comparing the horizon of the Brammerton pit with that of Aldeby, the author 
feels compelled to place the Crag of Aldeby and the upper beds at Brammerton in 
the same category, and consequently under the denomination of Norwich Crag. 
Fifty-six of the usual mollusks of the mammaliferous Crag are met with at Aldeby, 
viz. 40 bivalves, and 16 univalves. Also spines of Spatangus purpureus, and spines 
of an Echinus. Vertebra of a Delphinus, Otolites, and teeth of small fishes. ‘Teeth 
of a small Rodent. 
On the Thickness of the Chalk in Norfolk. By C. B. Rosz, MGS. Se. 
