138 
THE GEOLOGIST. 
liave hcc.n produoeil l)y l.lie Inst great convulsion that has affected our planet."* 
Omitting any opinion n\mn the cause of tliose deposits, Sir diaries Lyell gives 
the following deliuitlon of the diluvium: "Those accumulations of gravel and 
loose materiids which by some geoh)gists are said to have been produced by the 
action of a diluviau wave, or deluge, sweeping over tlie surface of the earth. "f 
More recent o])inions upon t!ie presumed agencies which have brought together 
the heterogeuons materials fornung the gravel and clay bt^ls, and deposited and 
spread them over their present sites, liavc led to the adoption of the term 
" drift," as more significantly expressing the modern views held on their mode 
of transport. The "drift," therefore, includes the series of beds of gravel, 
sand, loam, and boulder-clay, or till, the latter being but a northern provincial 
term for the former. 
My late friend, the highly intelligent geologist, Josluui Trimmer, whose well 
kno\\u intimate acquaintance with these superficial deposits, from an extended 
examination, has given high authority to his remarks upon them, was tlie first 
to adopt, if not to originate, their more defined division into " lower drift, till, 
or boulder-clay," " u])))er drift," and " warp of tlie drift. "| My respected 
friend afterwards divided his lower drift — f ill, or boulder-elay — into an upper 
and lower boulder-clay ; founding this division upon what he and others had 
observed in flic Suffolk cliffs, at and near to Gorleston. During the many 
agreeable gossips tliat I had with my late friend, I heard his views in relation 
to the above-mentioned divisions, and as frecpiently combated them, from not 
tax ing observed anything in West Norfolk to warrant them ; and since my 
residence at Yarmouth, after having repeatedly examined the cliff from Gorton 
to Gorleston, and otlier localities, I have seen nothing to shake my scepticism 
npou the subject. Trimmer wrote thus : " It appears that in the Gorleston 
cliffs there are two boulder-clays, separated by a mass of sand, which, on the 
authority of Woodward, has liitherto passed for the ' crag,' a term which has 
now become as indefinite as tliat of ' drift,' or ' drifts.' The lower boulder- 
clay is the tailing off of that so well known for its blocks of Scandinavian 
origin, and which extends over the north of Europe and into tlie eastern side of 
England. The upper boulder-clay is characterized by an abundance of oolitic 
detritus ;" and he proceeds to say that, " the former overlaps the latter, witli a 
mass of sand interposed." § 
It ap])ears from the ])crusal of this cited paper that there were anomalies in 
the structures of the superficial beds " which had perplexed" Mr. Trimmer; 
it also appears that tliese perplexities were removed by meeting with (for 
thus he wrote) " some boulders of gneiss on the beach ; and though during a 
rapid examination we found none actually embedded, Mr. Gunn assured me he 
had seen them in the cliff." || From having repeatedly examined fiiese cliffs, 
and having also dug into the so-caUed lower boulder-clay, or till, without meet- 
ing with a boulder of any kind i/t silu, I cannot assent to the existence of two 
boulder-clays — an u])per and a lower. 
Beneath the sand underlying the true boulder-clay a highly ferruginous loam, 
stained in places black by decomposed vegetable matter, exists. Into this bed 
I du^ to the depth of about five feet, and a trench, three feet by two, without 
meeting with anything but one portion of black flint, about the size of my open 
hand, with its angles rounded, and pebbles and small angular fragments of 
• ReliqujB DiluvianfB, p. 2. 1823. 
t Glossaiy in "The Principles of Geology." 
X " On the Geology of Noi-folk, &o." pubUshed in the Journal of the Royal Agricultural 
Society of England, vol. vii., part 2. 1847. 
§ " On the tJpper and Lower Bonldcr-clay of the Gorioston ClifFs." Quart. Jouraal of the 
Geological Society, vol. xiii. 1857. 
II Op. cit. 
