Quartzose Lower Silurian, with annelid burrows.
"The Student's Elements of Geology"
Sir Charles Lyell
At the base of the Cambrian strata in Sweden, which in the neighbourhood of Lake Wener are perfectly horizontal, lie ripple-marked quartzose sandstones with worm-tracks and annelid borings, like some of those found in the Harlech grits of the Longmynd.
"The Student's Elements of Geology"
Sir Charles Lyell
The free-swimming embryo of an aquatic annelid, being ovate and not ciliated all over, moves with one end foremost; and its differentiations proceed in conformity with this contrast of circumstances.
"Essays: Scientific, Political, & Speculative, Vol. I"
Herbert Spencer