Drifted Plant-Beds of the Upper Estuarine Series of Yorkshire

Abstract

I. I ntroduction . The Estuarine Series of Yorkshire consists of non-marine sandstones and shales, which reach a maximum thickness of about 1000 feet. The series is interrupted by three marine bands, all of which may not be present at any given locality. The complete sequence of Middle Jurassic rocks in Yorkshire, as stated by the Geological Survey, is as follows:— The term ‘Upper Estuarine Series’ appears to have been used for strata in Yorkshire for the first time by Fox-Strangways (1880, p. 3) to designate the strata above the Grey Limestone Series and below the Cornbrash. Of the marine bands, the Cornbrash and the Grey Limestone Series are by far the most constant, with the result that the Upper Estuarine Series is much the best defined of the three estuarine groups. The Upper Estuarine Series is exposed in the coast-section from the Wyke (2 miles west of Filey), as far as Ravenscar, where the outcrop turns inland. West of Ravenscar large areas of the moor are formed by outcrops of this series as far as Wheeldale Moor, where a pitch in the Cleveland Anticline brings up lower beds. North of the Esk valley, which cuts down into the Lias, a broad syncline preserves an outlier of the Upper Estuarine Series and the beds immediately above it. The object of the present paper is to describe and discuss the significance of the variations in the lithology and in the flora of the Upper Estuarine Series, and to show how the nature of