Vintage National Speleological Society Sweatshirt by Screen Stars
Here is a super cool sweatshirt from the 1980s by Screen Stars. 50/50 polyester and cotton blend, made in the USA. Black shirt with awesome textured graphic on the front. Medium weight, soft and comfy. The tag says Large, but here are the measurements taken laying flat. (refer to the last pic above to see how I measure shirts)
Chest (armpit to armpit) 20"
Shoulder to end of sleeve (including cuff) 24"