What you see here is the interior of a a house, gutted of sheetrock and insulation (thanks, Hurricane Sandy). For orientation, the image shows a junction of two walls, where a wall from the main block of the house meets the wall of a now enclosed porch. The pop quiz question: what would you call the material in the center of the image? In other words, identify the grooved wood pieces.
Preservation in Pink 
Not great at tests, usually, but 3/4″ Drop siding, methinks.
Ship lap siding with a decorative cove detail ??
I agree with Glen, but I was going to be less specific, and just say siding.
They look like clapboards that were just never removed.
In eastern Massachusetts this is called ‘novelty siding’. It was used primarily between WWI and WWII. It is a copy of what was used on George Washington’s estates. That may explain why it became popular – Colonial Revival, with all its iterations, was The Style for housing between the Wars.
Looks like someone got the answer right. I was going to answer, but I knew that would be cheating!
and Jane gets the win! Great job, Jane. I’m wondering if this novelty siding remains under the current siding anywhere else. We won’t know for a while, but I’ll be sure to share anything fun.
I uncovered it on a regular basis when I worked north of Boston. Anyplace you see a neighborhood of 1920’s houses that have been ‘updated’ you will probably find some.
Note to Linda O’Shea: I sometimes feel I am cheating when I answer, but I like it when others answer with the right information. It’s nice to know that I’m not the only one..