What was advertised in a colonial American newspaper 250 years ago today?

“A Parcel of good large Parchment Skins, for for Vessels Registers, to be sold by the Printer hereof.”
Advertising supplements were a fairly common feature of newspapers in the 1760s, especially publications printed in the largest American cities. Between news items, commercial notices, and paid announcements of various sorts, printers frequently ran out of space in the standard four-page issue. It made a lot of sense to distribute two-page supplements comprised solely of advertisements since it was advertising, rather than subscription fees, which really paid the bills.
Still, printers had to be careful in allocating resources to the advertising supplements. They had to weight the labor, time, and supplies they would expend against how quickly for frequently they published advertisements. Sometimes printers had more material than would fit in the standard issue but not enough to justify devoting an entire half sheet to a supplement. In such instances, they could opt to print the supplement on smaller sheets.
Such appears to have been the case with the Supplement to the South-Carolina Gazette and Country Journal from March 10, 1767. It is impossible to say so definitively based solely on digitized images of the newspaper from Accessible Archives. No provider of digital surrogates of eighteenth-century newspapers includes metadata concerning the dimensions of the page or columns relative to individual images. Doing so would be time consuming and prohibitively expensive, resulting in scholars and others having significantly less access to digitized sources at all.
Although I do not have access to original copies of the South-Carolina Gazette and Country Journal from 1767, the layout of the March 10 supplement contains all the indications of a smaller sheet that I have been able to confirm when working between digital surrogates and original copies of other newspapers. The regular issue contains three columns, but the supplement has two columns along with a third column of advertisements rotated to fit in the remaining space. The rotated advertisements are the same width as the others, indicating that type had not been reset, nor would it need to be reset to move any of the advertisements back into future editions of the regular issue.

In this instance, however, Charles Crouch engaged in even greater economy of space than his counterparts who adopted this trick in other newspapers. Rather than provide space between the rotated advertisements in the third column, he squeezed them together in order to fit in very short advertisements. On the front of the supplement, this resulted in a two-line advertisement oriented in a different direction than the others in the third column. On the other side, where he did not have to take space for the masthead into consideration, Crouch found room for two advertisements rotated in the same direction as the others in the additional column.

Charles Crouch worked to fill the March 10 supplement of his newspaper with as much advertising as he could possible fit on its pages. In so doing, he made room to promote products he sold (“WASTE Paper” and “good large Parchment Skins”) that otherwise would not have fit in the regular issue or the supplement.