Look for the sagittal suture – the squiggly line that runs the length of the skull – and note whether is it's completely fused. If it is, the remains are likely to be of someone older than 35.

and designated as Skull I of Locus L (Fig. 1), is the largest, with a cranial capacity of approximately 1,200 c.c. and with its coronal and sagittal sutures partly fused. The second skull (Skull ...

Look for the sagittal suture – the squiggly line that runs the length of the skull – and note whether is it's completely fused. If it is, the remains are likely to be of someone older than 35.