Introduction. At the outset I may at once state that with regard to these notes, while I hope hereby to render available some fresh information respecting the White Chalk of Yorkshire, there will be no attempt on my part to deal adequately with the whole subject. My chief aim will be to supply details which may forward and lighten the labours of its future investigators. My knowledge of the deposit is the result of the somewhat desultory observations made during the leisure hours of the twenty busy years which I spent in the vicinity of Flamborough Head. I commenced to collect fossils from this grand range of cliffs while still a school boy, and am glad even yet to enjoy occasionally the keen relish of the collector on the discovery of a “good specimen” in these rocks. As time went on I began to realise that in spite of the past labours of Phillips, Barrois, Blake, and Mortimer, there remained the necessity for a vast amount of patient and somewhat tedious investigation before our knowledge of the Yorkshire Chalk could be placed on a really satisfactory basis; and this led me to make measurements and records of some of the sections. Probably if I had remained much longer in the locality, and no other worker had come forward, I should eventually have taken the subject seriously in hand, and should have tried to submit the Upper and Middle Chalk to the same thorough study as Mr. W. Hill has accorded, ...