This is disk number one in the T1 set (the Seasons), and it must be Spring:
I see trees of green (well, they’ve grown mossy over time). And some daisies…
Those five oval shapes at the right are toes. Someone’s foot?
At the lower right corner of the triangle, I can make out a “CH” followed by an arrow. Because the Time Trail was designed by Charles Harrow, I think this must be his logo/signature.
On the left side of the triangle, there’s a smaller triangle with what looks like an “F” inside. If each disk has a different letter, then the letters from every disk in the set might spell a word.