can you post the picture of the structure. unless you have a subscription to the LA times you can’t read the article.
Picture here:
https://www.newscientist.com/article/2090183-neanderthals-built-mystery-underground-circles-175000-years-ago/
More pictures here:
https://www.google.com/search?q=neanderthals+stalagmites+circles+cave+france&safe=active&source=lnms&tbm=isch&sa=X&ved=0ahUKEwilmKCz2PbMAhUKMSYKHQDyA-MQ_AUIBygB&biw=1536&bih=708&dpr=1.25
(select images tab)